Comparison of Bone Histomorphology and Bone Mineral Density in Different Parts of Ovariectomized Osteoporosis Rats

抄録

This study aimed to investigate the changes of histomorphology and bone mineral density (BMD) change in different parts of ovariectomized osteoporosis rats. The six-month SD rats were randomly divided into the sham operation group and operation group, each consisting of 30 rats and an osteoporosis model was established by bilateral ovariectomy. The rats were harvested at 8 weeks, 12 weeks and 16 weeks after operation. The changes of bone morphology were observed by Masson staining on lumbar spine 3-5, right tibia and femur. BMD was measured at lumbar spine, left tibia and femur by Dual Energy X-ray Absorptiometry (DXA). Compared with sham operation group, the trabecular bones of the model group were sparse, irregularly arranged, unevenly distributed, the trabecular bone spacing was enlarged. A significantly increased amount of lipid droplets in the medullary cavity. The bone mass changes were most significant at 16 weeks after operation, reflected by the significant trabecula loss in the proximal tibia and distal femur, while in distal tibia and lumbar spine trabecula loss is less significant; BMD declines in all the four parts (P<0.01) and the differences in BMD, in descending order, are the proximal tibia, distal femur, proximal femur, and lumbar spine. In ovariectomized rats, the most sensitive areas to bone mass change are the proximal tibia and distal femur, which are major weight-bearing bones; non-weight-bearing areas show the most significant trabecula loss, and there is a positive correlation between the degree of trabecula loss and lipid accumulation in the medullary cavity, which makes non-weight-bearing areas optimal for osteoporosis research on postmenopausal rats.