绵羊椎体骨质疏松性生物力学模型的快速建立

目的运用微量注射泵向椎体内灌注盐酸及椎体整体浸泡的脱钙方法,快速建立绵羊腰椎骨质疏松性生物力学模型。方法(1)设计一款可拧入椎弓根带侧孔的圆柱形灌注连接器,做为椎体内部与注射泵的桥接装置。(2)将(3±0.5)岁新鲜绵羊腰椎48个,随机分为4个处理组:A组(0 h脱钙,即空白组),B组(2 h脱钙),C组(4 h脱钙),D组(6 h脱钙)。每组12个椎体。(3)检测各组椎体脱钙前后BMD;进行生物力学实验:测试最大轴向拔出力(Fmax)和最大抗压强度及其能量吸收值。同时各组取少量骨质制成组织切片,对脱钙后绵羊腰椎骨小梁微观结构进行观察。结果B、C、D处理组的BMD均值、最大轴向拔出力均值和最大抗压强度及其能量吸收值均值都低于A组(P0.01),且随脱钙时间的延长依次降低(P0.01)。椎体的最大轴向拔出力及最大抗压强度与BMD存在正相关关系,亦与BMD的下降值存在负相关。切片显示:B、C、D组椎弓根处骨小梁较A组骨小梁厚度明显变薄、数量减少,间距增宽,部分骨小梁连续性中断,骨髓腔扩大。结论运用微量注射泵向椎体内灌注盐酸及整体浸泡的脱钙方法,可快速、有效、可控的建立近似于骨质疏松状态下的生物力学模型,为在真正骨质疏松状态下的生物力学研究提供参考依据。

Rapid establishment of biomechanical model similar to lumbar vertebrae osteoporosis in sheep

Objective To place sheep lumbar vertebrae into a beher-glass filled with hydrochloric acid and infuse hydrochloric acid by infusion pump into it as an in-vitro method to establish a biomechanical model similar to osteoporosis in sheep lumbar vertebrae.Methods (1)Designing a cylindrical perfusion connector with side hole as a bridge connecting the vertebrae and the infusion pump.(2)Forty-eight fresh lumbar vertebrae from 3 ±0.5 years sheep,were randomly assigned to four groups by completely randomized design:Group A(no decalcification,the control group),Group B(decalcified with Hcl for 2 hours),Group C(decalcified with Hcl for 4 hours),Group D(decalcified with Hcl for 6 hours).12 verterbraes of each group.(3)Before and after decalcification all verterbrae of four groups were measured for bone mineral density(BMD),and for biomechanical experiments to test maximum axial pull-out strength(F_(max)),the maximum compressive strength and their energy absorption values,while several lumbar vertebraes of each group was harvested a small amount of Cancellous bone for histopathological examination to observemicrostructure of decalcified Cancellous bone in sheep verterbraes.Results There was a positive linear relationship among BMD and F_(max) or the maximum compressive strength,but negative relationship with the decline in the value of BMD.Means of the BMD,F_(max),the maximum compressive strength and energy absorption of group B,C and D were significantly lower than those of group A(P<0.01).while these values in each group are continuously falling with the extension of decalcification time. Histopathological examination revealed that the trabecular bones from pedicle became thinner, their number decreased and the space between them widened, and the antrum of bone marrow enlarged in group B, C and D compared with group A. Conclusion The method of acid decalcification may be useful for producing a quick, effective,and controllable biomechanical model similar to osteoporosis, it can provide reference data for biomechanical study in vivo model of osteoporosis.