[Effects of Different Preservation Methods on Mechanical Properties of Mouse Femur]

In order to establish the best procedure to store the femur samples from the biomechanical viewpoint,we compared the effects of different storage methods on the mechanical properties of mouse femurs.We obtained femurs surgically from twenty C57BL/6Jfemale mice,12 weeks old,and randomly divided them into 5groups,i.e.fresh control group,4% paraformaldehyde fixation group,4℃storage group,-20℃storage group and-80℃storage group,respectively,with five mice in each group.For the three low-temperature storage groups,each group was stored for 1week,2months,6months at their respective temperatures.After rewarming,three-point bending test was performed to test the load and deflection changes.The results showed that both the elastic modulus and deflection decreased significantly in the 4% paraformaldehyde group.The maximum load and elastic modulus of the samples in the 4 ℃ group after one week storage was significantly reduced;The mechanical properties were close to the fresh control group in the-20℃ group stored for 2months but the maximum load was also reduced after 6months.However,mechanical properties,such as elastic load,maximum load and elastic modulus,were not changed obviously in the-80 ℃ storage group.Accordingly,-80 ℃ cryopreservation had little influence on the mechanical properties of bone tissues,which proved that the temperature-80 ℃is a suitable one for long-term preservation.