The influence of phytoestrogens or estrogens on the proliferation of the rat endocervical mucosa

Abstract

SUMMARY INTRODUCTION Although estrogen therapy is widely used against post-menopausal symptoms, it can present adverse effects, including endometrial cancer. Soy isoflavones are considered a possible alternative to estrogen therapy. However, there are still concerns whether isoflavones exert trophic effects on the uterine cervix. OBJECTIVES To evaluate the histomorphometric and immunohistochemical alterations in the uterine cervix of ovariectomized rats treated with soy isoflavones (Iso). METHODS Fifteen adult Wistar rats were ovariectomized (Ovx) and divided into three groups: Group I (Ovx), administered with vehicle solution; Group II (OVX-Iso), administered with concentrated extract of Iso (150 mg/kg) by gavage; and Group III (OVX-E2), treated with 17β-estradiol (10 µg/kg), subcutaneously. After 30 days of treatments, the uterine cervix was fixed in 10% formaldehyde and processed for paraffin-embedding. Sections were stained with Hematoxylin and eosin for morphological and morphometric studies or subjected to immunohistochemistry for detections of Ki-67 and vascular endothelial growth factor-A (Vegf-A). The data obtained were subjected to statistical analysis (p ≤ 0.05). RESULTS We noted an atrophic uterine cervix in GI, whereas it was more voluminous in GII and even more voluminous in GIII. The thickness of the cervical mucosa was significantly higher in GIII, as compared to GI and GII. The cell proliferation (Ki-67) was significantly elevated in the estradiol and isoflavones treated groups, whereas Vegf-A immunoexpression was significantly higher in GIII, as compared to groups GII and GI. CONCLUSIONS Soy isoflavones cause less trophic and proliferative effects in the uterine cervix of rats as compared to estrogen.