| Objective:To investigate the effects of low molecular weight heparin(LMWH)on osteoporotic fracture healing in aged rats.Methods:The status of osteoporosis in 22-month-old male rats was confirmed by total body bone mineral density measurement.Fracture healing model was established by osteotomy with a wire saw and fixation with a Kirschner pin on left femur.60 model rats were randomized into two groups:30 for control group,and 30 for LMWH group.LMWH group was given daily subcutaneous injection of LMWH at dose of 100u/kg for total 10 days,while control group was given an equivalent volume of saline.The rats were scarified in 3 days,1,2,3,4,8 and 12 weeks after operation,the callus formation was monitored by histological and immunohistochemistry (transforming growth factor beta 1,TGF-beta 1)assessment,the bone mineral density measurement of the callus and the right femur was taken,alkaline phosphatase(ALP)activity as an index of bone formation was arrayed.Normal radiographs were taken at 12 weeks.Results:1.The histomorphological analysis revealed that the process of cartilage forming and transforming were postponed in LMWH group.The immunohistochemical results showed a decrease of expression of TGF-betal in LMWH group.2.LMWH group had lower bone mineral density.3.LMWH produced a significant decrease in serum ALP.4.Normal radiographs showed LMWH group had less callus formation.Conclusion:LMWH delays the osteoporotic fracture healing in aged rats.The most contributing factor associated with the poor fracture healing was inhibition of TGF-beta 1.
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