The Soybean Concentrated Extract Decreases Oxidative Stress and Have Trophic Effects in the Uterus and Vagian of Ovariectomized Rats

The diverse side effects that occur in women during postmenopause, even when they take hormone therapy, does not guarantee beneficial effects, since many women are insecure with the use of estrogens due to high risk of developing of breast and/or endometrium cancer. The ovariectomized rats model has been used with a view to menopausal women submitted to an alternative treatment with soy isoflavones. In this study we evaluated the proliferative and antioxidant potential of estrogen and isoflavones in the uterus and vagina of ovariectomized (Ovx) rats. We used 20 rats (Rattus norvegicus albinos), adult females at 3 months of age, divided into four groups: GI - sham-operated (estrous phase), GII- Ovx with receiving propyleneglycol; GIII - Ovx with receiving isoflavones (150mg/Kg) and GIV – Ovx with receiving 17beta-estrogen (10μg/Kg). At the end they were anesthetized and sacrificed and then the organs were removed and processed for immunohistochemistry and molecular biology assays. The superoxide anion was measured by DHE staining and the histomorphometry was analysed by H.E. Treatment with estrogen showed a largest increase of proliferation in uterus and vagina than isoflavones. These hypertrofic effects agree with the gene expression elevation of Ki67 and VEGF. Also, the group treated with isoflavones had lower levels of superoxide anion compared to the estrogen group, showing that isoflavones can reduce oxidative stress without promoting trophic effects. The treatment with estrogens after the cessation of gonad function in rats induces greater proliferation and increased oxidative stress, in particular to the genes associated to cyclins, Ki67 and VEGF-A, than isoflavones. Interestingly, the proliferative response to genistein is much less intense and we could observe that the levels of superoxide anion was decreased in this case. Financial Support: FAPESP and CNPq