Soy Isoflavone Improved Female Sexual Dysfunction of Mice Via Endothelial Nitric Oxide Synthase Pathway

Abstract

Introduction Female sexual dysfunction (FSD) is a common endocrine disease that impairs the quality of life for many women. The existing therapy strategies still have many disadvantages. It is necessary to explore new pharmacologic treatments that are effective and safe. Aim The aim of this study was to explore the effects of soy isoflavone (SI) on FSD in mice and the underlying mechanisms. Methods and Main Outcome Measures Laser Doppler flowmetry was used to determine vaginal blood flow. Serum hormone levels and histologic changes of the vagina were analyzed by enzyme-linked immunosorbent assay (ELISA) and by hematoxylin and eosin (H&E) and Masson’s trichome staining. The mRNA and protein expression of endothelial nitric oxide synthase (eNOS) was then evaluated by quantitative real-time polymerase chain reaction and western blot assays. Results Vaginal blood flow was found to be remarkably lower in adult mice, and SI was shown to increase vaginal blood flow in a dose-dependent manner ( P < .05). The results of ELISA and H&E and Masson’s trichome staining suggest that SI had a positive effect on FSD, as evidenced by the levels of hormones in serum and histologic changes of the vagina, which changed consistently. In addition, the level of eNOS was positively correlated with the concentration of SI, and eNOS inhibitor was able to reverse the improvement in sexual function induced by SI. Conclusion Our study demonstrated that SI could improve sexual function by upregulating the eNOS pathway. Therefore, SI might serve as a promising candidate for the treatment of sexual dysfunction. Zhang J, Zhu Y, Pan L, et al. Soy Isoflavone Improved Female Sexual Dysfunction of Mice Via Endothelial Nitric Oxide Synthase Pathway. Sex Med 2019; 7:345–351.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

“…The estrogen levels and the number of mature follicles significantly increased in isoflavone fed mice, suggesting that isoflavones promote the maturation of ovarian follicles [265]. In addition, isoflavone dose-dependently improved sexual dysfunction by activating the endothelial nitric oxide synthase (eNOS) signaling pathway via the estrogen receptor [265]. This shows that isoflavones in soybeans could improve sexual function in middle-aged female mice and confirms its potential for treating sexual dysfunction.…”

“…A study analyzed serum hormone levels, vaginal histological changes, and enzyme-linked immunosorbent assays in mice to confirm the effect of isoflavone on female sexual function and the underlying mechanisms. The results indicated that vaginal blood flow was significantly lower in the adult mice of the control group than in the mice that were fed isoflavone, in response to pelvic nerve stimulation in a dose-dependent manner [265]. The estrogen levels and the number of mature follicles significantly increased in isoflavone fed mice, suggesting that isoflavones promote the maturation of ovarian follicles [265].…”

“…The results indicated that vaginal blood flow was significantly lower in the adult mice of the control group than in the mice that were fed isoflavone, in response to pelvic nerve stimulation in a dose-dependent manner [265]. The estrogen levels and the number of mature follicles significantly increased in isoflavone fed mice, suggesting that isoflavones promote the maturation of ovarian follicles [265]. In addition, isoflavone dose-dependently improved sexual dysfunction by activating the endothelial nitric oxide synthase (eNOS) signaling pathway via the estrogen receptor [265].…”

Dietary Approaches to Women’s Sexual and Reproductive Health

“…Additionally, consumption of soy, a phytoestrogen, is shown to support increased vaginal blood flow, lubrication, and vaginal collagen content and decreased dyspareunia. [45][46][47] As a suppressor of free-radical generation, the benefits of soy plausibly include an antiinflammatory effect that enhances NO activity. 45,48 Fruits such as apples, watermelon, and cacao have been linked to enhanced vascular and sexual health.…”

“…[45][46][47] As a suppressor of free-radical generation, the benefits of soy plausibly include an antiinflammatory effect that enhances NO activity. 45,48 Fruits such as apples, watermelon, and cacao have been linked to enhanced vascular and sexual health. Daily apple consumption is associated with improved vaginal lubrication and general sexual function.…”