| Objective To investigate the effect of parathyroid hormone combined with estradiol on osteoporosis and its mechanism of action, and provide a theoretical basis for clinical drug use. Methods 100 female SD rats were randomly divided into 5 groups: sham operation group, ovariectomized group, parathyroid hormone group, estradiol group, and combination group, with 20 rats in each group. Firstly, osteoporosis animal model of ovariectomized rats were constructed. Assessments performed include BMD measurement of bone tissue, detection of biochemical markers related to bone metabolism, detection of bone metabolism markers, and observation of bone morphological changes. Results Compared with the sham operation group, BMD, the maximum femoral load, stiffness of the femur and serum Ca and P levels were significantly lower in the ovariectomized group (P<0.05), while the above-mentioned indicators in the combination group were significantly higher than those in the ovariectomized group (P<0.05). The levels of serum ALP, COL-I, OC and OPG in the ovariectomized group were significantly higher than the sham-operated group (P<0.05), while the above-mentioned indicators in the combination group were significantly lower than the ovariectomized group (P<0.05). The trabeculae of the ovariectomized group were rare, thin and sparse, fractured and separated, and the arrangement was loose and disordered. The bone tissue structure of the combined drug group was relatively complete, the trabecular bone morphological structure was relatively regular, the number was more, the density was uniform, and the continuity was good. Conclusion Parathyroid hormone combined with estradiol could regulate osteoporosis bone metabolism, increase bone density, improve biomechanical properties and bone histopathology, promote bone formation, inhibit bone resorption, and have bone protection effect. |