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[Effects of ovariectomy on fracture healing in female rats].

OBJECTIVE
To observe the effects of ovariectomy on fracture healing in female rats.


METHODS
Thirty-six 6-month-old female SD rats were divided into OVX group and SHAM group. The osteoporotic model was established by ovariectomy. The right femur was broken by operation at 8 weeks later. The rats were killed in batches at the end of 2, 4, 6, 8 weeks postoperatively for study. The examinations included the bone roentgenography, the histological appearance of bone calli and the biomechanical properties of right femur.


RESULTS
The density of calli was decreased obviously in OVX group. The line of fracture existed in OVX group while the line of fracture was unclear or disappeared in SHAM. In the OVX group, there were cartilages at the early callus formation stage, and there were small-sized osteoblasts and increased number of osteoclasts on the surface of osseous trabecula. The osseous trabecula became thinner and disrupted obviously in OVX group, and it became massive, thicker and closer gradually 8 weeks after fracture in SHAM group. The area of osseous trabecula in the SHAM group was bigger than that in the OVX group.


CONCLUSION
After ovariectomy, the absorption of bone prevails over osteogenesis, the osteoporotic changes occur, and the fracture healing is poor in quality.