|Year : 2021 | Volume
| Issue : 3 | Page : 232-241
Effects of soy isoflavone on cardiac dysfunction in geripause-like rats: comparisons with hormone-replacement therapy
Nashwa M Saied, Marwa M Abd-Rabo
Department of Hormone Evaluation, National Organization for Drug Control and Research, Giza, Egypt
|Date of Submission||24-May-2021|
|Date of Decision||25-Jun-2021|
|Date of Acceptance||12-Jul-2021|
|Date of Web Publication||16-Sep-2021|
Marwa M Abd-Rabo
MSc Biochemistry; Department of Hormone, National Organization for Drug Control and Research, Abo-Hazem Street, P.O. Box 12553, Harram, Giza
Source of Support: None, Conflict of Interest: None
Background Cardiovascular diseases are a primary cause of morbidity and mortality worldwide. The prevalence of cardiovascular disease as well as inflammation in postmenopausal women is higher than premenopausal women.
Objective The present study investigated cardiac dysfunction elicited by estrogen deprivation and aging and assessed a possible beneficial impact of isoflavones compared with estradiol-replacement therapy.
Materials and methods Forty aged female rats were equally divided into four groups. Except for sham-operated animals in group 1 (negative control), all other rats were ovariectomized. One month after surgery, animals were assigned to groups 3 and 4. Rats in the former group were treated with 17β-estradiol, 100 μg/kg, intramuscular, every other day. Animals in group 4 were administered soy isoflavones (SIF), 40 mg/kg/day orally. Treatments continued for 1 month.
Results and conclusion Compared with control rats, ovariectomized animals showed cardiac dysfunction and inflammation evidenced by dyslipidemia and elevated serum creatine phosphokinase and lactate dehydrogenase activity, angiotensin II, cardiac malondialdehyde and nitric oxide levels, and serum tumor necrosis factor-α and interleukin-6 levels. These impacts were concurrent with significant decreases in cardiac catalase activity and total antioxidant capacity. Treatment with SIF was more effective in mitigating inflammation and cardiac dysfunction compared with estradiol-replacement therapy. Histopathological examination of heart tissues supports these biochemical findings. SIF are a safe and well-tolerated alternative to estradiol for improving cardiac dysfunction elicited by menopause and age.
Keywords: geripause, soy isoflavones, estradiol, cardiovascular disease, inflammation
|How to cite this article:|
Saied NM, Abd-Rabo MM. Effects of soy isoflavone on cardiac dysfunction in geripause-like rats: comparisons with hormone-replacement therapy. Egypt Pharmaceut J 2021;20:232-41
|How to cite this URL:|
Saied NM, Abd-Rabo MM. Effects of soy isoflavone on cardiac dysfunction in geripause-like rats: comparisons with hormone-replacement therapy. Egypt Pharmaceut J [serial online] 2021 [cited 2022 Aug 18];20:232-41. Available from: http://www.epj.eg.net/text.asp?2021/20/3/232/326106
| Introduction|| |
Cardiovascular disease (CVD) is a primary cause of morbidity and mortality globally. In Egypt, CVD incidence is greater than 16% in people aged 40–64 . Remarkable progress in medical care is evident, especially in gynecology, for early detection of diseases and their related causes. This progress has led to an increase in life expectancy of women. Eskin and Troen  newly defined postmenopausal stages as ‘early’ (age 65) and ‘late’ (age 85) geripause.
The occurrence of CVD among women is low before menopause and gradually increases after the its onset , reflecting the critical role of sex hormones in the development of CVD ,. Hormone-replacement therapy (HRT) can ameliorate signs of estrogen deficiency, especially during menopause. Meanwhile, it leads to many adverse impacts such as cancer .
Several studies documented the postive correlation of circulating inflammatory markers and of CVD . An elevation in circulating tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), proinflammatory markers, in apparently healthy individuals, is a strong risk of CVD ,. Postmenopause and aging are factors that strongly induced an elevation in inflammatory markers, which are related to oxidative stress ,.
Soy isoflavones (SIF), a subclass of phytoestrogens, exist in many legumes and their products. The biological properties of SIF include antitumor , antimenopausal , anti-osteoporotic , antidyslipidemia , and anti-inflammatory activities . Further, isoflavones exert a protective effect against coronary heart diseases ,,. It might also be an effective treatment for cardiac dysfunction in ovariectomized rats. The aim of this research was to study the efficacy of such treatment on CVD following menopause against estradiol HRT.
| Materials and methods|| |
17β-estradiol (E2) was purchased from Sedico Pharmaceutical Company (Giza, Egypt). E2 was dissolved in olive oil to prepare for the administration dose of 100 μg/kg. SIF were purchased from Mepaco-Arab Company for Pharmaceuticals & Medicinal Plants (Cairo, Egypt). SIF was freshly suspended in 1 ml of Tween80 and distilled water for the administration of the dose of 40 mg/kg. Enzyme-linked immunosorbent assay (ELISA) rat serum estradiol kit was purchased from BioSource Co. Ltd. (California, USA). Serum activity of lactate dehydrogenase (LDH) and creatine phosphokinase (CK-MB) commercial kits were purchased from Reactivos GPL (Barcelona, Spain). Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) kits were purchased from Biodiagnostic (Cairo, Egypt). TNF-α, IL-6, and angiotensin II (ANG-II) ELISA kits were purchased from Cusabio (Germany). Total antioxidant capacity (TAC) commercial kit was purchased from Biodiagnostic.
All study protocols were approved by the Institutional Animal Ethics Committee at the National Organization for Drug Control and Research (approval no. 8/231/2019) and followed the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised 1996). Forty aged albino Wistar female rats, weighing 220–240 g, 12-month age, were obtained from the National Organization for Drug Control and Research. Animals were acclimated for two weeks at 25±2°C and 55±5% humidity under a 12‐h light/dark cycle and allowed free access to a standard diet and water before starting the experiment.
The animals were randomly allocated four groups, 10 rats per group. Group 1 rats received sham operations and served as a negative-control group. Animals in groups 2–4 were ovariectomized under aseptic conditions. Rats in groups 1 and 2 received intramuscular injections of olive oil every other day. One month after surgery, animals in groups 3 and 4 were treated with intramuscular injections of E2 dissolved in olive oil at a dose of 100 μg/kg, every other day , and SIF 40 mg/kg/day, orally , respectively. All treatments were continued for 1 month.
Ovariectomy was performed under aseptic conditions by removing bilateral ovaries under mild intravenous anesthesia with 60 mg/kg body weight thiopental . Treatments were delayed for 1 month after surgery to allow for recovery.
Preparation of cardiac homogenate for biochemical assays
On day 31, rats were sacrificed by decapitation under mild intravenous anesthesia with 60 mg/kg body weight thiopental. Blood samples were collected from the retro-orbital vein of all rats using heparinized glass capillary tubes. Blood samples were centrifuged at 3000 rpm for 20 min. Hearts were immediately removed and washed in ice-cold saline. Six hearts per group were homogenized in 0.05 M ice-cold phosphate buffer (pH 7.4). Homogenates were centrifuged at 3500 rpm for 20 min at 4°C, and the supernatant was used for measurement of biochemical parameters.
Determination of serum biochemical parameters
Each of rat serum estradiol, TNF-α, IL-6, and ANG-II were evaluated according to the manufacturer’s instructions of ELISA kits. Serum activity of LDH and CK-MB was assayed according to the manufacturer’s instructions of kinetic assay kits. Serum TC, HDL-C, and TG were assessed according to the manufacturer’s instructions of colorimetric kits. Low-density lipoprotein cholesterol (LDL-C) was calculated as LDL-C=TC-HDL-C-TG/5 . Atherogenic indexes (AI) I and II were calculated as TC/HDL‐C and LDL‐C/HDL‐C ratios, respectively .
Determination of antioxidant/oxidant parameters in cardiac tissues
Cardiac tissue homogenates were analyzed for several antioxidant/oxidant parameters. Catalase activity was measured spectrophotometrically by decreasing H2O2 concentration. Catalase-activity values were reported as U/mg protein . Malondialdehyde (MDA) level was analyzed at 535 nm by thiobarbituric acid-reactive substance estimation using standard method , and values were expressed as nmol MDA produced/g of tissue. Total nitrite and nitrates (NOx) were analyzed by a total reduction of nitrate to nitrite, under acidic condition, nitrite reacts with sulfanilamide to produce a diazonium ion, which is then coupled to N-(1-naphthyl) ethylenediamine (NED) to produce a chromophore azo product, which strongly absorbs at 545 nm. Total NOx is reported as μmol/g tissue . The TAC was estimated using commercial colorimetric kits based on an enzymatic reaction that involves the conversion of 3, 5, -dichloro-2-hydroxy benzensulfonate to a colored product by the residual H2O2 liberated from the sample, which strongly absorbs at 505 nm, the values were expressed as mmol/g tissue. The total protein level was determined in cardiac homogenates . All assays were analyzed with a double-beam spectrophotometer (Unicam Helios Alpha, Postdam, Germany).
After scarification, the remaining four hearts in each group were quickly dissected, cleaned with cold saline, and fixed in 10% neutral buffered formalin. Fixed tissues were dehydrated in a series of 50–100% ethanol solutions and embedded in paraffin. Serial 5-μm sections were cut and stained with hematoxylin–eosin .
Data are presented as means±SD. Statistical significance was assessed using one-way analysis of variance followed by Tukey’s multiple-comparison test . P value less than 0.05 was considered the threshold of significance. Data analyses utilized GraphPad Prism7 (GraphPad Software, San Diego, California, USA).
| Results|| |
Effect of ovariectomy and treatment on serum estradiol
Ovariectomized rats showed a significant decline in serum estradiol levels (57.63±5.93, −35%) compared with SH group (88.14±5.18), P value less than 0.05 ([Figure 1]). Groups 3 and 4 caused a significant rescue of serum E2 levels (131.60±5.60, 128% and 112.60±0.74, 95%, respectively) compared with ovariectomized rats (57.63±5.93), P value less than 0.05.
|Figure 1 Significant effects of ovariectomy (OVX), estradiol (OVX+E2), and soy isoflavones (OVX+SIF) on serum estradiol level. The data are presented as the mean±SD, n=6. aSignificant difference versus the sham (SH) group; bsignificant difference versus the ovariectomized (OVX) group; csignificant difference versus estradiol treatment. *P value less than 0.05, **P value less than 0.01, and***P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.|
Click here to view
Effect of ovariectomy and treatment on serum creatine phosphokinase and lactate dehydrogenase activity
A significant increase in serum CK-MB (186.5±13.82, 1581%) and LDH (2146±5.93, 888%) activities was found in ovariectomized rat animals, P value less than 0.05 ([Figure 2]), compared with serum CK-MB and LDH in SH group (11.09±1.927 and 217.2±6.343, respectively). Administration of estradiol and SIF induced a significant decline in serum CK-MB (78.62±4.86, −58% and 55.29±6.99, −70%, respectively) and serum LDH (870.80±15.92, −59% and 30.8±19.14, −80%, respectively), compared with ovariectomized animals, P value less than 0.05.
|Figure 2 Significant effects of ovariectomy (OVX), estradiol (OVX+E2), and soy isoflavones (OVX+SIF) on serum cardiac markers. (a) Creatine kinase (CK-MB) and (b) lactate dehydrogenase (LDH) activities. The data are presented as the mean±SD, n=6. aSignificant difference versus the sham (SH) group; bsignificant difference versus the ovariectomized (OVX) group; csignificant difference versus estradiol treatment. *P value less than 0.05, **P value less than 0.01, and*** P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.|
Click here to view
Effect of ovariectomy and different treatments on serum lipid profile
Ovariectomy induced dyslipidemia, evidenced by a significant increase in serum TC (165±26.02, 46.93%), TG (229.8±11.92, 46.74%), and LDL-C (85.18±7.33, 104.66%) and significant depletion of HDL-C (20.29±5.16, −58%), compared with SH group (112.30±7.94, 156.60±4.52, 41.62±10.45, and 48.75±8.64, respectively). SIF induced a significant depletion in serum TC (117.9±4.922, −28.55%), TG (86.63±9.19, −62.30%), and LDL-C (46.47±7.42, −45.44%), along with a significant increase in serum HDL-C (53.8±2.99, 165%). In addition, estradiol treatment exhibits a significant increase in serum TC (191.2±23.52, 15.88%), LDL-C (119.5±15.47, 40.29%), and HDL-C (31.63±7.812, 56%), with a significant depletion in serum TG (187.7±8.29, −18.32%). SIF treatment was superior to estradiol as indicated by re-establishment of normal lipid profiles ([Figure 3]).
|Figure 3 Significant effects of ovariectomy (OVX), estradiol (OVX+E2), and soy isoflavones (OVX+SIF) on serum lipid profile. (a) Total cholesterol (TC) and (b) triglycerides (TG), (c) high-density lipoprotein cholesterol (HDL-C), (d) low-density lipoprotein (LDL-C) levels. The data are presented as the mean±SD, n=6. aSignificant difference versus the sham (SH) group; bsignificant difference versus the ovariectomized (OVX) group; csignificant difference versus estradiol treatment. *P value less than 0.05, **P value less than 0.01, and***P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.|
Click here to view
Effects of ovariectomy and treatment on atherogenic indices
Ovariectomized rats showed a significant increase in AI-I (8.69±1.54, 265.52%) and AI-II (9.41±1.54, 360%), compared with SH group (2.38±0.52 and 2.05±0.44, respectively). Treatment with SIF induced a significant decrease in AI-I (2.20±0.12, −74.75%) and AI-II (2.66±0.20, −72%). In addition, treatment with estradiol exhibited a similar approach as SIF with a lesser effect as it induced a significant depletion in AI-I (5.873±1.508, −32.43%) and AI-II (6.40±1.37, −32%), compared with OVX group ([Figure 4]).
|Figure 4 Significant effects of ovariectomy (OVX), estradiol (OVX+E2), and soy isoflavones (OVX+SIF) on atherogenic indices. (a): Atherogenic index I, (b) atherogenic index II. The data are presented as the mean±SD, n=6. aSignificant difference versus the sham (SH) group; bsignificant difference versus the ovariectomized (OVX) group; csignificant difference versus estradiol treatment. *P value less than 0.05, **P value less than 0.01, and***P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.|
Click here to view
Effects of ovariectomy and treatment on antioxidant/oxidative parameters
Significant increases in the levels of MDA (150.9±21.0, 101%) and total NOx (239.8±7.9, 76%), along with significant depletion in catalase activity (0.05±0.02, −77%) and TAC level (7.28±1.12, −34%) in cardiac tissues of ovariectomized rats were observed, compared with SH group (74.9±5.8, 136.0±10.6, 0.21±0.07, and 11.1±2.32, respectively). Treatments with SIF and estradiol induced a significant depletion in MDA level (51.1±6.1, −66% and 76.8±11.6, −49%, respectively), total NOx (131.7±8.4, −45% and 134.0 ±21.9, −44%, respectively), where they induced a significant increase in catalase activity (0.216±0.04, 341%, and 0.182±0.04, 271%, respectively), compared with OVX group. Collectively, SIF treatment was as effective as estradiol-replacement therapy for renormalizing oxidant/antioxidant balance ([Table 1]).
|Table 1 Effect of ovariectomy, estradiol (ovariectomy+estradiol), and soy isoflavones (ovariectomy+soy isoflavones) on cardiac malondialdehyde, nitric oxide, catalyze, and total antioxidant capacity|
Click here to view
The data are presented as the mean±SD, n=10. (a) Significant difference versus the sham (SH) group; (b) significant difference versus the ovariectomized (OVX) group; (c) significant difference versus estradiol treatment. P value less than 0.05, P value less than 0.01, and P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.
Effects of ovariectomy and treatment on serum tumor necrosis factor-α, interleukin-6 and angiotensin II
Ovariectomy induced significant inflammation in OVX rats ([Figure 5]). Significant increases in serum TNF-α (91.71±8.13, 316.3%), IL-6 (80.7±7.73, 339.5%), and ANG-II (64.91±7.59, 641.8%) levels were observed following ovariectomy compared with SH group (22.03±2.41, 18.4±2.15, and 8.75±0.92, respectively). Both treatments of SIF and estradiol induced a significant depletion in serum levels of TNF-α (29.19±1.73, −68.17% and 38.77±2.1, −57.73%, respectively), IL-6 (26.15±1.773, −67.61% and 36.09±2.077, −55.30%, respectively), and ANG-II (14.88±0.895, −77.08% and 20.72±2.304, −68.08%, respectively), compared with OVX group. From the recorded result, treatment with SIF was more effective than estradiol for normalizing these serum parameters.
|Figure 5 Significant effects of ovariectomy (OVX), estradiol (OVX+E2), and soy isoflavones (OVX+SIF) on (a) tumor necrosis factor alpha (TNF-α); (b) interleukin-6 (IL-6); (c) angiotensin II (ANG-II). The data are presented as the mean±SD, n=6. aSignificant difference versus the sham (SH) group; bsignificant difference versus the ovariectomized (OVX) group; csignificant difference versus estradiol treatment. *P value less than 0.05, **P value less than 0.01, and***P value less than 0.001. Analysis of variance followed by Tukey’s correction for multiple comparisons.|
Click here to view
No histopathological alterations were found in control animals (group 1) and normal histological structure of the myocardium was noted ([Figure 6]a). Heart tissues from ovariectomized rats showed degeneration of the myocardium with congestion in the blood vessels and focal hemorrhage between myocardial bundles ([Figure 6]b). SIF-treated and E2-treated rats displayed no-to-mild histopathological changes in myocardial tissues ([Figure 6]c and d).
|Figure 6 (a) Normal histological structure of myocardium of the control group. (b) Cardiac tissue from ovariectomized rat dilated with congested blood vessel (v) with a thick hyalinized wall (arrow) (hematoxylin–eosin) (×200). (c) Cardiac tissue from ovariectomized rats treated with estradiol showing intact cardiomyocytes (arrow) (hematoxylin–eosin) (×200). (d) Cardiac tissue from ovariectomized rats treated with SIF, intact cardiomyocytes (arrow), cardiomyofibers, and hyalinized cardiomyofibers (arrow head) (hematoxylin–eosin) (×200). (hematoxylin–eosin) (×200).|
Click here to view
| Discussion|| |
Treatment of postmenopausal women with HRT causes several adverse impacts, such as endometriosis, breast cancer, and stroke ,. SIF is a promising alternative treatment to improve cardiac dysfunction resulting from menopause and aging.
Twelve-month-old female rats were ovariectomized to induce geripause-like status and cardiac dysfunction . In line with the current results, previous researches documented a significant depletion of serum estradiol following 1 month of ovariectomy ,. Ovariectomy produces cardiac dysfunction, evidenced by increases in serum LDH and CK-MP activity, oxidative insult in cardiac tissues assessed by increased MDA and nitric oxide (NO) levels, and concomitant depletion in catalase activity and TAC levels. Also, significant increases in serum TNF-α and IL-6 concentrations and decreased serum estradiol levels were observed.
Plasma AIs are indicators of risk for cardiac dysfunction associated with dyslipidemia . Dyslipidemia concurrent with elevated AI-I and AI-II was found in ovariectomized rats ([Figure 3] and [Figure 4]). Depletion in serum estradiol after menopause or ovariectomy may downregulate genes and enzymes involved in lipolysis and fatty acid metabolism and thus elicit dyslipidemia ,.
The dose of SIF orally administered in the current study was within the range of daily intake of isoflavones for Asian populations (25–50 mg/day) . Treatment with SIF renormalized the levels of serum estradiol, consistent with several researches ,. Additional studies are needed to assess the mode of action for increased serum estradiol levels caused by SIF.
Ovariectomized animals treated with SIF showed renormalized lipid profiles and AIs. SIF may induce hypolipidemic effects in at least three ways. First, SIF may cause a reduction in ghrelin levels. This potent growth hormone promotes white adipose tissue lipogenesis via a hypothalamic-mediated mechanism. Second, SIF might induce an increase in bile acid degradation, which decreases intestinal absorption of cholesterol. Third, SIF may activate AMPK, which enhances fatty acid oxidation in the liver and adipocytes ,,.
Ovariectomized rats showed oxidative insult, evidenced by a significant rise in cardiac MDA and total NOx, concurrent with significant depletion in cardiac catalase activity and antioxidant capacity. Previous studies report dyslipidemia associated with increased free-radical production. This excess free-radical formation results in lipid peroxidation and generation of MDA. Free radicals also lead to decreasing antioxidant enzyme activity (e.g. catalase) and TAC ,,,,. NO is a free radical derived from the oxidative deamination of L-arginine nitric oxide synthase (NOS) with the reducing cofactor, tetrahydrobiopterin (BH4). Total cardiac nitrate (NOx) levels in ovariectomized rats could be attributed to depletion of estrogen after gonadectomy. Such depletion upregulates NOS and increases the production of NOx ,. Conversely, BH4 is vulnerable to oxidation by ROS through activation of NADP(H) (NOX4). NOX4 upregulation promotes conversion of molecular oxygen to superoxide ions. Increased superoxide results in uncoupling of endothelial NOS (eNOS) and increased production of ONOO−, along with NO production that causes endothelial dysfunction . The present study reflects an inflammatory process ovariectomized rats, shown by increases in serum inflammatory markers, TNF-α and IL-6. Inflammation may stimulate inducible NOS (iNOS) for NO metabolite production ,.ANG-II is a potent vasoconstrictor in vascular smooth muscle cells. AI-I acts through the liberation of ROS via NOX4. Again, excess ROS may lead to uncoupling of NOS and endothelial dysfunction . Ovariectomized rats in the present study show a significant increase in ANG-II level, consistent with the findings of Jennings et al. ,.
Elevation of serum CK-MP and LDH enzymes in ovariectomized animals might be attributed to an increase in ROS in cardiac tissues following tissue injury, an increase in cell permeability, or membrane rupture. Such damage allows release of intracellular constituents into the blood ,. Ovariectomy thus induces a series of oxidative insults that induce CVD-like responses and inflammation.
SIF and estradiol treatments were compared for their efficacy in attenuating biochemical changes characteristic of CVD. Several studies document the beneficial effects of 17β estradiol treatment for mitigating oxidative stress. The authors attribute this action to downregulation of NOX4, and increased SOD and catalase activity ,.
Treatment of ovariectomized rats with SIF in the present study mitigated oxidative insult and protected the heart from OVX-induced damage. SIF was superior to estradiol in modulating serum ANG-II levels. These findings may reflect the superior antioxidant properties of SIF. SIF is a complex mixture of antioxidant compounds, such as α-tocopherol, glycosides and derivatives, and phenolic acids. The latter chemical group includes syringic, vanillic, caffeic, ferulic, p-coumaric, and p-hydroxybenzoic acids that are potent free-radical scavengers . In addition, the antioxidant activity of SIF could be attributed to its activities as estrogen-receptor modulator in attenuating ROS production . Antihyperlipidemic activity of SIF could be attributed to genistein, which is a major isoflavone component in SIF, it could decrease cholesterol synthesis by suppressing cholesterol esterification and increase LDL-receptor activity, as well as augmented sterol regulatory element-binding protein 2-regulated genes, which is a cholesterol catabolic gene . The decrease of ROS production could be ascribed to antihyperlipidemic activity of SIF, that may lead to inhibition of LDL oxidation . Based on previous studies and current results, the antioxidant activities of SIF may inhibit ANG-II-induced cardiovascular dysfunction ,. A reduction in ROS following treatment with SIF could explain the rescue of both CK-MB and LDH enzyme levels and the attenuation of inflammation, as assessed by downregulation of IL-6 and TNF levels ,,,.
The above biochemical data are confirmed by histopathological findings in cardiac tissue. Histopathology induced by ovariectomy was reversed by both estradiol and SIF treatments.
| Conclusion|| |
Aged ovariectomized rats display a series of biochemical disruptions and accompanying pathohistological alterations in serum and cardiac tissues. These changes are major risk factors for cardiovascular dysfunction. SIF were used in this study as an alternative to estradiol-replacement therapy. SIF showed superior activity in mitigating oxidative insult, dyslipidemia, ANG-II, and inflammation-induced cardiovascular damage in aged ovariectomized rats.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Kaptoge S, Pennells L, Bacquer D, De, Cooney MT, Kavousi M, Stevens G et al.
World Health Organization cardiovascular disease risk charts: revised models to estimate risk in 21 global regions. Lancet Glob Heal 2019; 7:e1332–e1345.
Eskin BA, Troen BR. Geripause: a newly defined postmenopausal phase. Menopause Manage 2004; 13:12–17.
Mendelsohn ME, Karas RH. The protective effects of estrogen on the cardiovascular system. Epstein FH, editor. New England Journal Medicine. Massachusetts: Massachusetts Medical Society; 1999. 1801–1811.
Grodstein F, Stampfer M. The epidemiology of coronary heart disease and estrogen replacement in postmenopausal women. Prog Cardiovasc Dis 1995; 38:199–210.
Ezzat-Zadeh Z, Kim JS, Chase PB, Arjmandi BH. The cooccurrence of obesity, osteoporosis, and sarcopenia in the ovariectomized rat: a study for modeling osteosarcopenic obesity in rodents. J Aging Res 2017; 2017:1454103–1454103.
Abd-Rabo MM, Georgy GS, Saied NM, Hassan WA. Involvement of the serotonergic system and neuroplasticity in the antidepressant effect of curcumin in ovariectomized rats: comparison with oestradiol and fluoxetine. Phyther Res 2019; 33:387–396.
Davison S, Davis SR. New markers for cardiovascular disease risk in women: impact of endogenous estrogen status and exogenous postmenopausal hormone therapy. J Clin Endocrinol Metab 2003; 88:2470–2478.
Schumacher SM, Naga Prasad SV. Tumor necrosis factor-α in heart failure: an updated review. Curr Cardiol Rep 2018; 1:117.
Fontes JA, Rose NR, Čiháková D. The varying faces of IL-6: from cardiac protection to cardiac failure. Cytokine 2015; 74:62–68.
Milan-Mattos JC, Anibal FF, Perseguini NM, Minatel V, Rehder-Santos P, Castro CA et al.
Effects of natural aging and gender on pro-inflammatory markers. Braz J Med Biol Res 2019; 52:e8392.
Kim OY, Chae JS, Paik JK, Seo HS, Jang Y, Cavaillon JM, Lee JH. Effects of aging and menopause on serum interleukin-6 levels and peripheral blood mononuclear cell cytokine production in healthy nonobese women. Age (Omaha) Springer 2012; 34:415–425.
Sahin I, Bilir B, Ali S, Sahin K, Kucuk O. Soy isoflavones in integrative oncology: increased efficacy and decreased toxicity of cancer therapy. Integr Cancer Ther 2019; 18:1–11.
Chen LR, Ko NY, Chen KH. Isoflavone supplements for menopausal women: a systematic review. Nutrients; 2019; 11:2649–2664.
Yanaka K, Higuchi M, Ishimi Y. Anti-osteoporotic effect of soy isoflavones intake on low bone mineral density caused by voluntary exercise and food restriction in mature female rats. J Nutr Sci Vitaminol 2019; 65:335–342.
Barańska A, Błaszczuk A, Polz-Dacewicz M, Kanadys W, Malm M, Janiszewska M, Jędrych M. Effects of soy isoflavones on glycemic control and lipid profile in patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials. Nutrients 2021; 13:1886–1905.
Jheng HF, Hayashi K, Matsumura Y, Kawada T, Seno S, Matsuda H et al.
Anti-inflammatory and antioxidative properties of isoflavones provide renal protective effects distinct from those of dietary soy proteins against diabetic nephropathy. Mol Nutr Food Res 2020; 64:2000015.
Taku K, Melby MK, Nishi N, Omori T, Kurzer MS. Soy isoflavones for osteoporosis: an evidence-based approach. Maturitas 2011; 70:333–338.
Shao Y, Yu Y, Li C, Yu J, Zong R, Pei C. Synergistic effect of quercetin and 6-gingerol treatment in streptozotocin induced type 2 diabetic rats and poloxamer P-407 induced hyperlipidemia. RSC Adv Roy Soc Chem 2016; 6:12235–12242.
Gil-Izquierdo A, Penalvo JL, Gil JI, Medina S, Horcajada MN, Lafay S et al.
Soy isoflavones and cardiovascular disease epidemiological, clinical and −omics perspectives. Curr Pharm Biotechnol 2012; 13:624–631.
Nomikos G, Spyraki C, Kazandjian A, Sfikakis A. Estrogen treatment to ovariectomized rats modifies morphine-induced behavior. Pharmacol Biochem Behav 1987; 27:611–617.
Messina M, Nagata C, Wu AH. Estimated Asian adult soy protein and isoflavone intakes. Nutr Cancer 2006; 55:1–12.
Lasota A, Danowska-Klonowska D. Experimental osteoporosis − different methods of ovariectomy in female white rats. Rocz Akad Med Białymst 2004; 49 Suppl 1:129–131.
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972; 18:499–502.
Cai G, Shi G, Xue S, Lu W. The atherogenic index of plasma is a strong and independent predictor for coronary artery disease in the Chinese Han population. Medicine (Baltimore) 2017; 96:e8058.
Claiborne A. Catalase activity. In: Greenwald RA, editor. Handbook of methods for oxygen free radical research. Boca Raton, Florida: CRC Press 1985. 283–284
Mihara M, Uchiyama M. Determination of malonaldehyde precursor in tissues by thiobarbituric acid test. Anal Biochem 1978; 86:271–278.
Green LC, Wagner DA, Glogowski J, Skipper PL, Wishnok JS, Tannenbaum SR. Analysis of nitrate, nitrite, and [15N]nitrate in biological fluids. Anal Biochem 1982; 126:131–138.
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the folin phenol reagent. J Biol Chem 1951; 193:265–275.
Brancroft JD, Stevens A, Bancroft JD, Stevens A. Theory and practice of histological technniques. 4th eds. Livingstone, New York, London, San Fr. York, London, San Francisco, Tokyo: Churchil Livingstone 1982.
Kim H-Y. Statistical notes for clinical researchers: post-hoc multiple comparisons. Restor Dent Endod 2015; 40:172.
Oh KJ, Chae MJ, Lee HS, Hong H Do, Park K. Effects of korean red ginseng on sexual arousal in menopausal women: Placebo-controlled, double-blind crossover clinical study. J Sex Med 2010; 7:1469–1477.
Rosano GMC, Vitale C, Marazzi G, Volterrani M. Menopause and cardiovascular disease: the evidence. Climacteric 2007; 10:19–24.
Machi JF, Silva Dias D, da Freitas SC, Moraes OA, de Silva MB, da Cruz PL et al.
Impact of aging on cardiac function in a female rat model of menopause: role of autonomic control, inflammation, and oxidative stress. Clin Interv Aging 2016; 11:341–350.
Oestergaard S, Sondergaard BC, Hoegh-Andersen P, Henriksen K, Qvist P, Christiansen C et al.
Effects of ovariectomy and estrogen therapy on type II collagen degradation and structural integrity of articular cartilage in rats: implications of the time of initiation. Arthritis Rheum 2006; 54:2441–2451.
Abd-Rabo MM, Georgy GS, Saied NM, Hassan WA. Involvement of the serotonergic system and neuroplasticity in the antidepressant effect of curcumin in ovariectomized rats: Comparison with oestradiol and fluoxetine. Phyther Res 2019; 33:387–396.
Thaung Zaw JJ, Howe PRC, Wong RHX. Postmenopausal health interventions: time to move on from the Women’s Health Initiative? Ageing Res Rev 2018; 48:79–86.
Ko SH, Kim HS. Menopause-associated lipid metabolic disorders and foods beneficial for postmenopausal women. Nutrients 2020; 12:202–227.
Pantaleão TU, Mousovich F, Rosenthal D, Padrón ÁS, Carvalho DP, Costa VMC Da. Effect of serum estradiol and leptin levels on thyroid function, food intake and body weight gain in female Wistar rats. Steroids 2010; 75:638–642.
Lim DW, Kim JG, Kim YT. Effects of dietary isoflavones from Puerariae radix on lipid and bone metabolism in ovariectomized rats. Nutrients 2013; 5:2734–2746.
Khatib N, Gaidhane S, Gaidhane AM, Simkhada P, Gode D, Zahiruddin QS. Ghrelin: ghrelin as a regulatory peptide in growth hormone secretion. J Clin Diagn Res 2014; 8:MC13–MC17.
Abdelrazek HMA, Mahmoud MMA, Tag HM, Greish SM, Eltamany DA, Soliman MTA. Soy isoflavones ameliorate metabolic and immunological alterations of ovariectomy in female Wistar rats: Antioxidant and estrogen sparing potential. Oxid Med Cell Longev 2019; 2019.
Cederroth CR, Vinciguerra M, Gjinovci A, Kühne F, Klein M, Cederroth M et al.
Dietary phytoestrogens activate AMP-activated protein kinase with improvement in lipid and glucose metabolism. Diabetes 2008; 57:1176–1185.
Yang RL, Shi YH, Hao G, Li W, Le GW. Increasing oxidative stress with progressive hyperlipidemia in human: relation between malondialdehyde and atherogenic index. J Clin Biochem Nutr 2008; 43:154–158.
Stocker R, Keaney JF. Role of oxidative modifications in atherosclerosis. Physiol Rev 2004; 84:1381–1478.
Itabe H. Oxidative modification of LDL: its pathological role in atherosclerosis. Clin Rev Allergy Immunol 2009; 37:4–11.
Abbas AM, Sakr HF. Simvastatin and vitamin e effects on cardiac and hepatic oxidative stress in rats fed on high fat diet. J Physiol Biochem 2013; 69:737–750.
Rivera-Mancía S, Jiménez-Osorio AS, Medina-Campos ON, Colín-Ramírez E, Vallejo M, Alcántara-Gaspar A et al.
Activity of antioxidant enzymes and their association with lipid profile in Mexican people without cardiovascular disease: An analysis of interactions. Int J Environ Res Public Health 2018; 15:2687–2702.
Ceccatelli S. Expression and plasticity of NO synthase in the neuroendocrine system. Brain Res Bull 1997; 44:533–538.
Ronchetti SA, Machiavelli LI, Quinteros FA, Duvilanski BH, Cabilla JP. Nitric oxide plays a key role in ovariectomy-induced apoptosis in anterior pituitary: interplay between nitric oxide pathway and estrogen. PLoS One 2016; 11:e0162455.
Kuzkaya N, Weissmann N, Harrison DG, Dikalov S. Interactions of peroxynitrite, tetrahydrobiopterin, ascorbic acid, and thiols: Implications for uncoupling endothelial nitric-oxide synthase. J Biol Chem 2003; 278:22546–22554.
Naseem KM. The role of nitric oxide in cardiovascular diseases. Mol Aspects Med 2005; 26:33–65.
Münzel T, Camici GG, Maack C, Bonetti NR, Fuster V, Kovacic JC. Impact of oxidative stress on the heart and vasculature: part 2 of a 3-part series. J Am Coll Cardiol 2017; 70:212–229.
Hitomi H, Kiyomoto H, Nishiyama A. Angiotensin II and oxidative stress. Curr Opin Cardiol 2007; 22:311–315.
Jennings BL, George LW, Pingili AK, Khan NS, Estes AM, Fang XR et al.
Estrogen metabolism by cytochrome P450 1B1 modulates the hypertensive effect of angiotensin II in female mice. Hypertension 2014; 64:134–140.
Jennings BL, Moore JA, Pingili AK, Estes AM, Fang XR, Kanu A et al.
Disruption of the cytochrome P-450 1B1 gene exacerbates renal dysfunction and damage associated with angiotensin II-induced hypertension in female mice. Am J Physiol 2015; 308:F981–F992.
Abdulqawi K, El-Mahalaway AM, EL-Gohary OA, Rezk AY, Wahba O. The biochemical and histopathological effects of estrogen replacement therapy on the heart of ovariectomized female rats subjected to myocardial infarction. Evid Based Women’s Health J 2013; 3:165–172.
Shaer SS, El Salaheldin TA, Saied NM, Abdelazim SM. In vivo ameliorative effect of cerium oxide nanoparticles in isoproterenol-induced cardiac toxicity. Exp Toxicol Pathol 2017; 69:435–441.
Hao F, Gu Y, Tan X, Deng Y, Wu ZT, Xu MJ, Wang WZ. Estrogen replacement reduces oxidative stress in the rostral ventrolateral medulla of ovariectomized rats. Oxid Med Cell Longev 2016; 2016:1–8.
Ceravolo GS, Filgueira FP, Costa TJ, Lobato NS, Chignalia AZ, Araujo PX et al.
Conjugated equine estrogen treatment corrected the exacerbated aorta oxidative stress in ovariectomized spontaneously hypertensive rats. Steroids 2013; 78:341–346.
Yoon GA, Park S. Antioxidant action of soy isoflavones on oxidative stress and antioxidant enzyme activities in exercised rats. Nutr Res Pract 2014; 8:618–624.
Bhathena SJ, Velasquez MT. Beneficial role of dietary phytoestrogens in obesity and diabetes. Am J Clin Nutr 2002; 76:1191–1201.
Lee YM, Choi JS, Kim MH, Jung MH, Lee YS, Song J. Effects of dietary genistein on hepatic lipid metabolism and mitochondrial function in mice fed high-fat diets. Nutrition 2006; 22:956–964.
Rizzo G. The antioxidant role of soy and soy foods in human health. Antioxidants 2020; 9:1–25.
Pabich M, Materska M. Biological effect of soy isoflavones in the prevention of civilization diseases. Nutrients 2019; 11:1660.
Richardson SI, Steffen LM, Swett K, Smith C, Burke L, Zhou X et al.
Dietary total isoflavone intake is associated with lower systolic blood pressure: the coronary artery risk development in young adults (CARDIA) study. J Clin Hypertens 2016; 18:778–783.
Tang Y, Li S, Zhang P, Zhu J, Meng G, Xie L et al.
Soy isoflavone protects myocardial ischemia/reperfusion injury through increasing endothelial nitric oxide synthase and decreasing oxidative stress in ovariectomized rats. Oxid Med Cell Longev 2016; 2016:1–14.
Perumal DK, Adhimoolam M, Ivan EA, Rajamohammed A. Effects of soy isoflavone genistein on lipid profile and hepatic steatosis in high-fat-fed Wistar rats. Natl J Physiol Pharm Pharmacol 2019; 9:856–861.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]