脱钙皮质骨基质的拉伸力学性能研究

TENSILE MECHANICAL CHARACTERISTICS OF DECALCIFIED CORTICAL BONE MATRIX

目的探讨脱钙皮质骨基质厚度与拉伸力学性能的关系,为将其作为组织工程支架材料奠定实验基础。方法取市售新鲜小牛胫骨,常规快速脱钙制备脱钙皮质骨基质,大体观察其颜色、质地等物理性状,并进行脱钙检测。将脱钙皮质骨基质沿径向纵切成不同厚度的片材,并根据厚度分为4组(n=16),分别为A组100～300μm,B组300～500μm,C组500～700μm,D组700～1 000μm;对每组标本进行拉伸性能和组织学观测。结果大体观察显示脱钙皮质骨基质经H2O2处理后呈乳白色,柔韧性好,富有弹性。脱钙皮质骨基质的脱钙率达97.6%。A组强度及弹性模量明显小于B、C、D组(P<0.05),B、C、D组间比较差异均无统计学意义(P>0.05);脱钙皮质骨基质刚度随厚度增加呈逐渐增大趋势,A组刚度显著低于B、C、D组(P<0.05),B、C组低于D组(P<0.05),B、C组间差异无统计学意义(P>0.05);各组极限应变差异均无统计学意义(P>0.05)。组织学观察各组均可见典型骨单位结构,其最大直径范围为102～325μm,平均最大直径为182μm。结论骨单位的完整性对脱钙皮质骨基质的力学性能有重要影响;脱钙皮质骨基质作为组织工程支架材料,在厚度>300μm时可保持其拉伸力学性能。

Objective To evaluate the tensile mechanical characteristics of decalcified cortical bone matrix with different thicknesses so as to provide an experimental basis for the scaffold of tissue engineering.Methods Decalcified cortical bone matrix was prepared from fresh bovine tibia with rapid decalcification techniques.Its physical characteristics including colour,texture,and so on,were observed.Then the decalcified rate was calculated.Decalcified cortical bone matrices were radially cut into slices with different thicknesses along longitudinal axis and divided into 4 groups： group A（100-300 m）,group B（300-500 m）,group C（500-700 m）,and group D（700-1 000 m）.Then the slice specimens of each group were characterized with tensile test and histological examination.Results General observation showed that decalcified cortical bone matrix with hydrogen peroxide treatment was ivory white with good elasticity and flexibility.The decalcified rate was 97.6%.The tensile strength and elastic modulus of groups B,C,and D were significantly higher than those of group A（P 0.05）;there was no significant difference among groups B,C,and D（P 0.05）.The stiffness in 4 groups increased gradually with the increasing thickness,it was significantly lower in group A than those in groups B,C,and D（P 0.05）,and in groups B and C than that in group D（P 0.05）.While there was no significant difference in ultimate strain within 4 groups（P 0.05）.Histologically,intact osteon was observed in every group,with an average maximum diameter of 182 m（range,102-325 m）.Conclusion The mechanical properties of decalcified cortical bone matrix might depend on the integrity of the osteons.Slices with thickness of 300 μm or more could maintain similar mechanical properties when decalcified cortical bone matrix is used as a scaffold for tissue engineering.