Objective To investigate the effect of GSYG on osteoporosis and the apoptosis and autophagy of the bone cells in ovariectomized rats mediated by Beclin 1/Bcl-2. Methods Rats were divided into five groups randomly, including the sham group, the model group, the GSYG low-dose, medium-dose, and high-dose groups [1.25, 2.5, and 5 g/(kg·d)]. The levels of P1NP and β-CTX in serum were determined with ELISA. The changes of bone mineral density and microstructure of the femur were determined with micro-CT. The morphological changes of the rat femurs were observed with HE staining. The apoptosis of osteocytes was observed with TUNEL staining. The changes of LC3 in the bone were observed with immunohistochemical staining. The levels of Bcl2, Bax, cleaved caspase-3, cleaved PARP, LC3, and Beclin1 in the proximal tibia of rats were detected with Western blotting. Finally, the action between Beclin1 acted with Bcl-2 was detected with co-immunoprecipitation. Results Compared to those in the model group, the levels of P1NP and β-CTX in GSYG medium and high dose groups decreased significantly (P<0.01), and the microstructure of bone the GSYG-treated groups improved significantly (P<0.01). In addition, the number of bone trabeculae increased significantly. Furthermore, osteocyte apoptosis decreased markedly (P<0.01). The expression of Bcl-2 in GSYG groups were markedly up-regulated (P <0.01), while Bax expression was significantly down-regulated (P<0.05 or P<0.01). Besides, the cleaved caspase-3 and cleaved PARP expression were markedly down-regulated in the GSYG high-dose group (P<0.01), while LC3-II /I and Beclin1 expression in medium-dose and high-dose GSYG groups increased significantly (P<0.01). Immunohistochemical staining results showed that LC3 protein increased significantly in response to the GSYG treatment (P <0.05 or P<0.01). The results of co-immunoprecipitation showed that Beclin1 and Bcl-2 had stronger interaction in the model group than that in sham group, while the combination of Beclin1 and Bcl-2 decreased in the GSYG high-dose group. Conclusion GSYG inhibits the development of osteoporosis in ovariectomized rats. Its mechanism is related to its regulation of apoptosis and autophagy mediated by Beclin 1/Bcl-2. |