| Objective To study the effect of simvastatin combined with estradiol on osteoporosis in rats. Methods Seventy-five female SD rats were randomly divided into 5 groups: sham operation group, castration group, simvastatin group, estradiol group, and combined drug group, with 15 rats in each group. Ovariectomized rat osteoporosis model was established. Different drug intervention was applied. Bone metabolism related biochemical indicators and bone biomechanical indicators were detected. Bone mineral density (BMD) and bone mineral content (BMC) were determined. Bone morphological structure was observed with HE staining. Results The biochemical parameters of serum bone metabolism (ALP, BGP, PICP, TRAP) in the ovariectomized group were significantly higher than those in the sham operation group (P<0.05). They were lower in simvastatin group, the estradiol group, and the combination group than in the castrated group. They were the lowest in the combination group (P<0.05). BMD, BMC, and bone biomechanical parameters (maximum load, maximum stress, maximum displacement and stiffness) in the ovariectomized group were significantly lower than those in the sham operation group (P<0.05). They were higher in simvastatin group, the estradiol group, and the combination group than in the castrated group. The increase was most significant in the combination group (P<0.05). The trabecular bone in the ovariectomized group was sparsely arranged and disordered. Reticular structure, massive fibrous tissue, and many vacuolar fat cells appeared in the medullary cavity. In the combined drug group, a complete bone structure appeared. The number of trabecular bone increased, showing dense, uniform, and a network structure. The fat cells reduced significantly. Conclusion Simvastatin combined with estradiol regulates bone metabolism, increases BMD and bone minerals, improves bone biomechanics and bone histomorphology, and plays an anti-osteoporosis and bone protection role. |