去负荷对大鼠骨计量学和骨质的影响

目的 观察去负荷对骨质显微结构的影响，并对骨小梁的结构进行定量化评定，探讨去负荷骨局部因子、骨强度及骨量的变化。方法 将SD雄性大鼠分为2组，对照组(FAC)和悬吊组(SC)，每组9只，实验期为21d。观察大鼠骨小梁的显微结构，骨中局部因子，骨力学性能及骨量的变化。结果 悬吊组骨小梁结构紊乱，骨小梁面积比(％ Tb．Ar)、骨小梁厚度(Tb．Th)、成骨表面(Ob．S)均显著下降，骨小梁间隙(Tb．Sp)显著增加，破骨细胞数(Oc．N)无显著变化；骨中碱性磷酸酶(ALP)活性含量显著下降，一氧化氮(NO)含量显著增加，骨强度、骨密度、骨矿盐含量(BMC)和骨胶原含量减少。结论 去负荷导致骨显微结构退化，骨局部因子含量改变，骨强度和骨量减少。

Effects of Hindlimb Unloading on Bone Histomorphometry and Bone Mass in Rats

Objective To study the effects of hindlimb unloading on bone histomorphometry, bone local growth factor,bone biomechanical properties and bone contents in rats. Method Male SD rats were arranged into free active control group (CON) and tail-suspended group (TS) with 9 rats in each group. The experiment lasted for 3 weeks. Bone histomorphometry, bone local growth factor, biomechanical properties and bone contents were measured before and after tail suspension. Result Structure of the trabecular bone was disorganized. Compared with CON, trabecular bone volume(%Tb.Ar), mean trabecular plate thickness(Tb.Th), osteoblast surface(Ob.S) were significantly reduced in TS. The eroded surface(Oc.N/BS) tended to be higher, though not significant at this stage of tail suspension; alkaline phosphatase (ALP) activity in the tibia were significantly reduced, but NO content in the femoral trunk was significantly decreased; bone biomechanical properties, bone mineral content(BMC), bone density(BD) and bone collagen density(BCD) in the femur were significantly reduced. Conclusion Hindlimb unloading may lead to regression of bone microstructure, change of bone local growth factor content, reduction of bone biomechanical properties and bone content.