老龄雄性大鼠去势后的骨骼生物力学变化

Changes of biomechanical properties in bones of castrated old male rats

目的探讨建立男性骨质疏松症动物模型。方法14月老龄雄性大鼠去势4个月后,取股骨和L3椎体,单光子吸收测量(SPA)法和定量计算机断层扫描(QCT)技术分别检测骨量,并分别进行3点弯曲实验和纵向压缩实验,对侧股骨测量其水平面几何学改变。结果假手术组和去势组股骨骨密度分别为(0.406±0.010),(0.389±0.08)g/cm2;股骨强度极限分别为(135.1±36.3),(102.1±18.5)MPa;弹性模量分别为(3.24±1.36),(1.91±0.47)GPa。L3骨矿含量分别为(82.3±11.5),(51.9±8.7)mg/cm2,强度极限分别为(20.4±8.2),(13.2±3.2)MPa。去势组大鼠股骨骨量减少4.2%(P<0.001),股骨强度极限、弹性模量分别减少24%和41%(P<0.05)。椎体骨量减少36.9%(P<0.001),强度极限降低37%(P<0.05),但弹性模量无明显改变。结论老龄雄性大鼠去势后造成皮质骨和骨松质骨量生物力学改变,这种改变以皮质骨更为明显,可以作为男性骨质疏松症的动物模型。

AIM: To establish the animal model of male osteoporosis.METHODS: The 14 month old male rats were castrated. Four months later,the three point bending test of femora and longitudinal compression test of lumbar vertebrae were performed, and the geometric changes of the cross section of contralateral femur were also measured.RESULTS:The bone mineral density of femur in the castration group and in pseudo operation group was (0.406±0.010)and(0.389±0.08)g/cm2 respectively;The intensity maximum of femur was(135.1±36.3)and(102.1±18.5)MPa; the elastic modulus was (3.24±1.36)and(1.91±0.47)GPa respectively;the bone mass of L3 was (82.3±11.5) and (51.9±8.7) mg/cm2 respectively and the intensity maximum was(20.4±8.2),(13.2±3.2)MPa respectively.The bone mass of femur in castration group decreased 4.2%(P< 0.001),the intensity maximum and elastic modulus decreased 24%and 41%respectively(P< 0.05).The bone mass of vertebra decreased 36.9%(P< 0.001), the intensity maximum decreased 37%(P< 0.05), but the elastic modulus showed no change.CONCLUSION: In old male rats, castration leads to a decrease in bone mass and biomechanical properties of cancellous and cortical bone, especially cancellous bone, and it can be an ideal animal model of osteoporosis in male.