Effects of the phytoestrogen genistein on the development of the reproductive system of Sprague Dawley rats

Abstract

OBJECTIVES:Genistein is known to influence reproductive system development through its binding affinity for estrogen receptors. The present study aimed to further explore the effect of Genistein on the development of the reproductive system of experimental rats.METHODS:Eighteen post-weaning female Sprague Dawley rats were divided into the following groups: (i) a control group that received vehicle (distilled water and Tween 80); (ii) a group treated with 10 mg/kg body weight (BW) of Genistein (Gen 10); and (iii) a group treated with a higher dose of Genistein (Gen 100). The rats were treated daily for three weeks from postnatal day 22 (P22) to P42. After the animals were sacrificed, blood samples were collected, and the uteri and ovaries were harvested and subjected to light microscopy and immunohistochemical study.RESULTS:A reduction of the mean weekly BW gain and organ weights (uteri and ovaries) were observed in the Gen 10 group compared to the control group; these findings were reversed in the Gen 100 group. Follicle stimulating hormone and estrogen levels were increased in the Gen 10 group and reduced in the Gen 100 group. Luteinizing hormone was reduced in both groups of Genistein-treated animals, and there was a significant difference between the Gen 10 and control groups (p<0.05). These findings were consistent with increased atretic follicular count, a decreased number of corpus luteum and down-regulation of estrogen receptors-α in the uterine tissues of the Genistein-treated animals compared to the control animals.CONCLUSION:Post-weaning exposure to Genistein could affect the development of the reproductive system of ovarian-intact experimental rats because of its action on the hypothalamic-pituitary-gonadal axis by regulating hormones and estrogen receptors.

Crateva adansonii DC, an African ethnomedicinal plant, exerts cytotoxicity in vitro and prevents experimental mammary tumorigenesis in vivo

“…Moreover, the lowest (75 mg/ kg) dose of C. adansonii extract turned to be more efficient than the higher one (300 mg/kg). This may be due to the saturation of estrogen receptors by bioactive compounds present in the extract which consequently will lead to the phenomena of down regulation of receptor induced by the higher dose of the extract; this phenomenon is common with phytoestrogen (Zin et al, 2013).…”

Genistein exposure inhibits growth and alters steroidogenesis in adult mouse antral follicles

“…Such studies have shown that embryonic or neonatal exposures to genistein cause the development of multi-oocyte follicles, increase atresia (Medigovic et al ., 2012), and reduce fertility in rodents (Britt et al ., 2005; Jefferson et al ., 2005; Chen et al ., 2007; Jefferson et al ., 2007; Jefferson et al ., 2009; Cimafranca et al ., 2010; Zhuang et al ., 2010). In addition, one study indicates that exposure to genistein after weaning alters circulating estradiol levels in rats, with the lower dose (10 mg/kg for three weeks) increasing estradiol levels and the higher dose (100 mg/kg for three weeks) inhibiting estradiol levels (Zin et al ., 2013). …”

“…Genistein inhibits steroidogenesis or steroidogenic enzymes in cultured rat pre-antral follicles (Myllymaki et al ., 2005), rat granulosa-luteal cells (Whitehead and Lacey, 2000), and porcine granulosa, theca, or luteal cells (Gregoraszczuk et al ., 1999; Nynca and Ciereszko, 2006; Tiemann et al ., 2007; Basini et al ., 2010). Exposure to genistein also alters follicle growth (Zhuang et al ., 2010), induces follicular atresia (Zin et al ., 2013), and inhibits oocyte maturation (Chan, 2009). However, these studies have not examined the effects of genistein on the intact, adult antral follicle, the functional unit of the ovary.…”

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“…Therefore, a competition between estrogens and phytoestrogen is attributed to estrogen receptors, and in addition to estrogenic properties, antiestrogenic properties of plants on reproductive system can also be observed 34 . In general, phytoestrogens do not appear to have strong phytoestrogenic properties, and even their application does not show adverse and antiestrogenic effects in cases where the endometrial thickness is normal 29 .…”

“…Estrogen increases endometrial thickness by affecting glands and endometrial cells and increasing the blood flow of the functional layer. Besides, in plants, phytoestrogens can also increase endometrial thickness by imitating estrogens functions and binding to alpha-type estrogen receptor (ER-α) 34 .…”