中国20～60岁男性腰3椎体松质骨生物学和生物力学参数的变化

Changes in vertebral biological and biomechanic parameters of L3 vertebral cancellous bone of China male aged 20～60 years

目的:观察中国20～60岁男性腰3(L3)椎体松质骨密度和生物力学的变化。方法:取捐献的新鲜中国男性L3椎体32个,年龄20～60岁,分成20～、30～、40～和50～60岁4个年龄组,每组8个椎体。常规操作去除L3椎体周围软组织及附属结构,只保留椎体部分。沿椎体正中矢状面将椎体切成左右两半,均保留上下终板,制成规则试件,一部分行密度测量,另一部分行生物力学实验。结果:①随着年龄的增长,骨胶原交联能力下降,胶原纤丝粗细不等,走向一致,但排列松散、稀疏、紊乱,连接相邻较粗纤丝的更细的胶原纤丝的走向杂乱无章。②与20～岁组比较,30～60岁的L3椎体松质骨表观密度和体积比均逐渐减小(F=8.280、10.600,P均<0.001),但30～60岁各年龄组间差异无统计学意义(P>0.05)。③与20～岁组比较,50～60岁组的L3椎体松质骨弹性模量和极限应力均减小(F=4.330、9.800,P均<0.05)。结论:中国20～60岁男性椎体松质骨的密度、极限载荷和弹性模量逐渐减小,骨密度和生物力学随年龄的变化可能是中国男性骨质疏松和骨折危险性增加的根本原因。

Aim：To observe the density and biomechanics of vertebral cancellous bone of 20~60 year-old Chinese males.Methods：A total of 32 fresh L3 vertebral bodies were donated from Chinese men with age ranging from 20 to 60 years,and were divided into four groups（20~,30~,40~,50~60 years,8 in each group）.The conventional lumbar separation was operated by removing soft tissue,subsidiary structure and leaving only the vertebral body.The vertebral body was cut into two halves along median sagittal plane to make specimens,retaining the upper and lower end plates.The specimens were divided into two equal parts.One part was randomly selected for the biomechanical experiments,and the other part was used for the density experiments.Results：With aging,collagen cross-linking capacity declined,the thicknesses of collagen fibrils were various,ranging almost the same,but loosing,sparse,disorder,and the finer collagen fibrils between the thick filaments were disorganized.Compared with those of 20~ years group,the apparent density and volume ratio of the other three groups decreased（F=8.280,10.600,P0.001）,but there were no significant differences among the three groups（P0.05）.Compared with those of 20~ years group,the elastic modulus and ultimate stress of 50~60 years group reduced（F=4.330,9.800,P0.05）.Conclusion：From 20 to 60 years old,the density,elastic modulus and ultimate stress of cancellous bone of Chinese males decreased with aging,which may lead to an increasing risk of osteoporosis and fracture.