Abstract:

Objective To observe the changes of femur biomechanics in osteoporosis rats and to explore the effect of collagen content and morphology on the changes.  Methods Normal 45 nullimating female 7 month SD rats were randomly divided into three groups, A: the sham-operation group; B: the De-ovary group; C: the De-ovary and calcitonin group. Osteoporosis models were given different interventions and then were killed 20 weeks later. Biomechanical properties of the femur were determined, and  the HYP and the BMD were determined. Morphology of the femur bone trabecula and of the bone collagen were observed by HE dyeing and by masson triad color dyeing, respectively.  Results  BMD of osteoporosis rats was（0.264±0.004）g/cm² in A group，（0.179±0.004）g/cm²　in B group，and （0.249±0.005g/cm²）in C group. HYP of rats was(0.227±0.046)mg/kg in A group， (0.194±0.032)mg/kg in B group，and (0.217±0.044)mg/kg in C group. There were evident differences in shape of collagen, bone density, bone biomechanics, content of hydroxyproline between B and C groups. There was a linear correlation between hydroxyproline and bone density and biomechanical parameters. The results showed that there was a correlation between the HYP content and postmenopausal osteoporosis, especially osteoporosis fracture.  Conclusion  There were obvious changes in femur biomechanics and collagen. Changes of bone collagen are the main reason of biomechanical property changing. Enhancing collagen of the bone can improve biomechanical properties of the bone and decrease the osteoporosis fracture rate.

Key words: Bone collagen; Osteoporosis; Femur; Bone biomechanical property; Rats, Wistar