[Histomorphometric analysis in ovariectomized rat with osteoporosis].

OBJECTIVE: To establish the pattern of bone loss of Sprague-Dawley rats after ovariectomy, to investigate and assess the pattern of bone remodeling in ovariectomized rats and the therapeutic action of nilestriol and levenorgestrel. METHODS: Histomorphometric analysis for bone tissues was performed with the instrument of computerized image analysis. RESULTS: The trabecular bone volume, mean trabecular thickness, and trabecular bone perimeter were all significantly decreased (P < 0.01) in ovariectomized rats in the 14th week postsurgery compared to the sham operated group. But the osteoblastic index, osteoclastic index, resorptive surface of trabecular, and trabecular surface covered by osteoblast were significantly increased (P < 0.01). There was no significant difference between the treatment group and the sham operated group. CONCLUSIONS: The pattern of bone loss of rats after ovariectomy has been established successfully. The study provides evidence that the cause of bone loss in the ovariectomized rats is attributable to the increase of bone turnover and negative imbalance in bone remodeling process. The treatment of nilestriol and levenorgestrel may decrease the bone turnover and correct the imbalance to cure the osteoporosis.