Protective effect of vaginal resveratrol administration on joint tissues in ovariectomized rats: Targeting mTOR and сaspase 3.

INTRODUCTION: Estrogens play a considerable role in maintaining bone and articular cartilage homeostasis. Menopause provokes joint disorders due to metabolic syndrome and altered signaling pathways. Phytoestrogen resveratrol was demonstrated to provide chondroprotective and osteoprotective effects. However, the mechanisms of such action of Resveratrol are still being explored. AIM: The study aims to determine the effect of Resveratrol on the joints and its therapeutic mechanism in ovariectomized rats. MATERIAL AND METHODS: The study was carried out on Wistar female rats that were divided into three groups, including control animals; ovariectomized rats (OVX); and the OVX group treated with an intravaginal gel containing Resveratrol (0.5 % 0.1 mL, daily 28 days). Knee joint tissues (articular cartilage, subchondral plate, subchondral bone) were assessed by histomorphometry. The expression of mTOR, PTEN, Caspase 3 and BCL-2 in articular cartilage and subchondral bone were evaluated immunohistochemically. RESULTS: Resveratrol treatment of OVX rats prevented weight gain by 17 % (P < 0.001), demonstrating the systemic effect on metabolic pathways. Although there were no statistically significant differences in the thickness of articular cartilage between groups, OVX rats possessed degenerative changes in chondrocytes, associated with the enhanced expression of mTOR (P < 0.001) and Casp-3 (P = 0.005). Resveratrol decreased mTOR (P = 0.007) and Casp-3 (P = 0.011) expression in chondrocytes, reducing degenerative changes. At the same time, resveratrol attenuated the deterioration of trabecular bone in OVX rats (P = 0.002). This effect was through the up-regulation of BCL-2 (P = 0.018) and down-regulation of Casp-3 expression (P < 0.001). CONCLUSIONS: Intravaginal administration of resveratrol provided systemic effects and ameliorated joint tissue structure and signaling in OVX rats through stimulation of BCL-2 and reduced Casp-3 expression.

Resveratrol Effects on the Reproductive System in Ovariectomized Rats: Deciphering Possible Mechanisms.

Phytoestrogen resveratrol (R) has been demonstrated to benefit human reproductive health. However, R bioavailability and pharmacokinetics are still problematic under oral supplementation. We used an experimental vaginal gel with R and hyaluronic acid (HA) to improve bioavailability and pharmacokinetic properties. The study aimed to assess the impact of vaginal R-HA gel on the reproductive system in ovariectomized rats. Methods: The study was carried out on Wistar female rats. It investigated the body weight, tail temperature, vaginal pH, estrogen and progesterone blood levels, and immunohistochemical biomarkers (COX2, Casp-3, Bcl-2, and VEGF). Animals were divided into control animals; ovariectomized rats (OVX); and OVX group treated with vaginal 0.5% R-HA gel (0.5%, 0.1 mL, daily 28 days). Results: The R-HA gel's therapeutic effect was manifested by slowing weight gain by 17% (p < 0.001), less pronounced symptom of fever at the root of the tail by 9% (p < 0.001) and lowering the vaginal pH to 4.4−4.5 compared with OVX rats. The anti-inflammatory effect and the reduction of COX-2 expression in vagina were accompanied by antiapoptotic impact of RA-H on endometrium, associated with the decreased Casp-3 expression (p < 0.001) and elevated Bcl-2 score in endometrial glands (p = 0.01). Together with enhanced VEGF expression in endometrial glands (p < 0.001) and stromal cells (p = 0.007), these changes prevented endometrial atrophy (p < 0.001) after ovariectomy. Thus, this study substantiates the feasibility of developing an innovative topical drug with R and HA for treating hypoestrogenic disorders.