动物造模,卵巢早衰大鼠模型 z-bio 2022-01-24 478

　　RESULTS: TG-induced premature ovarian failure rat model BTR restored abnormal estrous cycle and improved ovarian index: During the experiment, one animal in the POF model group died for unknown reasons, and the subsequent data were discarded. We studied the estrous cycle and ovarian index of different groups of animals. After 5 days of TG induction, food intake, locomotor activity and stimulus responses were reduced in POF model group compared with control group. In the three BTR-treated groups, animals' food intake remained unchanged and no abnormal behavior was observed. Within 15 days of TG induction, most animals in the POF model group showed cessation of estrous cycles, and the remaining estrous cycles were longer than control animals. However, this TG-induced abnormal estrous cycle was clearly counteracted by BTR in a dose-dependent manner. High doses of BTR showed similar estrous cycles as control animals.

　　After the treatment, the ovaries of each group were anatomically examined, and the ovarian index of each group was calculated. The ovarian index of POF model group was significantly lower than that of control group. The TG-induced reduction in ovarian index could be counteracted by different concentrations of BTR in a dose-dependent manner. These results suggest that BTR can restore abnormal estrous cycle and ameliorate TG-induced premature ovarian failure.

　　The effect of BTR on serum E2, FSH, and P levels in TG-induced premature ovarian failure model: During premature ovarian failure, the ovary cannot function normally under appropriate gonadotropin stimulation, so it cannot produce normal sex hormones. Previous studies have reported that POF is associated with decreased serum E2 levels and increased serum P, FSH, and T levels. The serum E2, FSH, P and T levels of animals in each group were measured. To explore the effect of BTR on the secretion of these reproductive hormones. Compared with the control group, the serum E2 level of the POF model group was significantly decreased, and the FSH, P, T levels were significantly increased. These TG-induced changes were significantly prevented by BTR in a dose-dependent manner, suggesting that BTR ameliorated POF-related abnormal secretion of reproductive hormones.

　　The effect of BTR on primary follicles, growing follicles and corpus luteum function in a TG-induced premature ovarian failure model: POF manifests as a decrease in the number of developing follicles, thereby affecting reproductive activity. Histological analysis of ovarian sections was performed to investigate the effect of BTR on primary follicle, growing follicle and corpus luteum function in TG-induced premature ovarian failure model. Stained sections of the control group showed normal cortex and medulla with multiple mature follicles at different stages. The corpus luteum was visible, but there was no follicular ovarian cyst or corpus luteum hematoma. No inflammatory cell infiltration or ovarian fibrosis was found in either the cortex or medulla. In the POF model group, the histological abnormalities of the cortex and medulla, the number of primordial follicles and primary follicles were significantly reduced, and the number of oocytes degenerated and matured follicles were less. Ovarian interstitial fibrosis, corpus luteum degeneration and necrosis, inflammatory cell infiltration, and vasodilation were also seen in the sections. For the three BTR-treated groups, slices showed that TG-induced pathological changes were significantly attenuated by BTR. The histology of BTR middle and high group was close to that of normal tissue and control group.

　　The effect of BTR on the expression of VEGF and VEGFR2 in the ovary of TG-induced premature ovarian failure model rats: Histological analysis of ovarian sections showed that the vascular morphology changed in each group. Immunohistochemical staining was performed to observe the intraovarian expression of BTR on two key pro-angiogenic factors, VEGF and VEGFR2, in a TG-induced premature ovarian failure model. Compared with the control group, samples from the POF model group showed a significant decrease in the intensity of immunohistochemical staining, and the decrease in staining was significantly recovered by BTR in a dose-dependent manner. These findings were also confirmed by the results of a semiquantitative immunohistochemical assessment. TG-induced POF reduces ovarian VEGF and VEGFR2 expression.

　　BTR protects TG-induced premature ovarian failure rat model and reduces granulosa cell apoptosis: To study the protective effect of BTR on granulosa cell apoptosis in TG-induced premature ovarian failure rat model. The ovarian staining sections of the control group showed that most of the granulosa cells were healthy and there was no sign of apoptosis. In the POF model group, the cells were dense and irregular in shape, and the nuclei were small and dense. In addition, in the late stages of apoptosis, nuclei are fragmented, resulting in vacuolization and apoptotic bodies. The BTR-treated group showed that most of the granulosa cells had intact cell membranes and clear nuclei. Quantitative analysis showed that the proportion of apoptotic cells decreased in all BTR-treated groups, especially in the BTR high-dose group. The results showed that BTR could protect TG-induced premature ovarian failure model rat ovarian granulosa cells from apoptosis. To further verify the results of histological examination, the expression of several apoptosis-related proteins Bcl-2, Bax and caspase-3 in BTR was studied. Compared with the control group, bcl-2 in the premature ovarian failure model group was significantly decreased, and bax and caspase 3 were significantly increased. However, these changes were reversed by BTR in a dose-dependent manner.

　　Conclusion: The current study shows that BTR is effective in the treatment of TG-induced premature ovarian failure in rats. Analysis of histological and immunohistochemical results indicated that promoting angiogenesis and anti-apoptosis are two mechanisms that may be affected by BTR.