不同年龄尾吊鼠负重骨骨代谢及力学性能变化

Comparison of bone metabolism and mechanical properties of weight-bearing bone in tail-suspended rats at different ages

目的 比较尾吊脱负荷对不同发育阶段大鼠负重骨骨代谢和生物力学性能的影响程度。方法 将年幼 2月龄和成年 6月龄雄性SD大鼠分别随机分至尾吊组 (S2M、S6M)和对照组 (C2M、C6M)。 4周后 ,生物材料试验机测负重骨生物力学性能 ,灰化法和原子吸收分光光度法测骨矿盐和钙含量。结果 (1)尾吊引起鼠胫骨体积、湿重、干重和骨矿物盐含量明显减少 (P <0 0 1) ,其中 ,胫骨体积、湿重减少与年龄有关 (P <0 0 5 ) ;(2 ) 2月龄和 6月龄尾吊鼠骨矿盐含量分别减少 4 3 2 %、2 78% ,与骨钙丢失程度 0 5 3 %、3 0 5 %并不一致 ;(3 )除弹性负荷外 (P >0 0 5 ) ,尾吊使负重骨各力学指标显著下降 (P <0 0 1) ,且最大桡度和最大负荷下降与月龄有关 (P <0 0 5 ) ;

Objective To make a comparative study of the effects of tail suspension on bone metabolism and mechanical properties of weight bearing bone in rats at different age,aiming to make clear the effects of age on bone response to disuse by tail suspension Methods 2 month old and 6 month old rats were subjected to hindlimb elevation by tail suspension for up to 4 wk,respectively The mechanical properties of femurs and the growth and material contents of tibia were measured Results (1)Bone material loss of the tibiae occurred in both groups of rats undergoing the test ( P<0 01 ),whose effect on the volume and mass of fresh tibiae was age related ( P<0 05 ) (2)The degree of mineral loss was not consistent with calcium loss in rats at different ages (3)Except for elastic deformation ( P>0 05 ), both structural and biomechanical properties altered significantly after tail suspension test ( P<0 01 ),and the changes of maximum deformation and maximum load were related to the age of the rats ( P<0 05 ) Conclusion The differences in the response of weight bearing bone to disuse by tail suspension are age related