The Establishment And Evaluation Of The Animal Model Of Disused Osteoporosis

Part OneObjectiverThe animal model is a useful method for the study of disused osteoporosis .The main aim of our research is to establishment of the animal model of disused osteoporosis .Methods: We used 21 rabbits. The right hind-limb of each rabbit was fixed by the cast as the experimental side, and the left hind-limb was free as the self-control side. All animals lived in a large place. Seven nimals were sacrificed in 6, 10 and 12 weeks after fixation. The tibiae were taken out bilaterally. The structural mechanical properties of these bones were measured with the compression method by our self-fixed mechanical testing machine. The trabecular bone volume /sponge bone volume (TBV/SBV), mean trabecular width (MTW) were measured with bone histomorphormetry.Result: The slope of stress-strain curve of the test side was less than the control side in all groups (P<0.05). The TBV/SBV of the test side was lower than the control side in all groups(P<0.05) .Conclusion: Fixing the hind-limb of the animal with cast is an available method of establishment of the animal model of disused osteoporosis .Part twoObjective: We designed and fixed a mechanical testing machine , convenient for measurement of the mechanical properties of bone.Methods: The mechanical testing machine contants frame, driven unit, specimen handling unit, mechanics measurement unit, strain measurement unit and data recording unit. Before holding the test object , loading axial must be adjusted. Then mechanics measurement unit, strain measurement unit are fixed to zero point. Data recording unit works during applying load on the test object. 10 risen sticks were divided in two groups. The mechanical properties of the risen sticks of one group were measured using a standard mechanical testing machine. The other sticks were measured using our self-fixed mechanical testing machine.The Young's modulus of two groups were compared with t-test.Result: The difference of Young's modulus between two groups has no statistics signification(P>0.05).Conclusion: The principles of our self-fixed mechanical testing machine and normal mechanical testing machine are same and the error of our self-fixed mechanical testing machine is allowable. It can be used in research.