深低温冷冻去细胞肌腱移植的组织学和生物力学研究

Histological and biomechanical studies of deep-frozen acellular tendon grafting

目的通过对比深低温冷冻去细胞肌腱和未经处理肌腱移植的组织学和生物力学特性，研究肌腱内去细胞对移植肌腱愈合的影响，探讨肌腱愈合的机制。方法取96只Wistar大鼠，随机分为实验组和对照组，制备跟腱缺损模型。实验组大鼠行深低温冷冻去细胞肌腱移植，对照组行自体肌腱移植。术后1、2,4、8周处死大鼠取移植肌腱，HE染色后在光学显微镜视下进行形态学观察，Ⅰ型和Ⅲ型胶原行免疫组化染色观察及图像分析，并测量移植肌腱最大载荷和弹性模量生物力学参数。结果随着时间的延长，Ⅰ型和Ⅲ型胶原表达量增加，其中1、2周时对照组表达水平高于实验组（P〈0．05），4、8周时两组表达差异无统计学意义。生物力学结果显示1、2周时对照组弹性模量和最大载荷均高于实验组（P〈0．05），而4、8周时两组差异无统计学意义。结论深低温冷冻去细胞肌腱移植和自体移植远期效果相似，因此深低温冷冻去细胞肌腱可用于肌腱移植。

Objective To study the influence of decellularization on tendon graft healing and investigate the mechanism of tendon healing by comparing the histological and biomechnaical characteristics of deep-frozen acellular tendon grafting and autologous fresh tendon grafting. Methods Ninety-six Wistar rats were randomly divided into the experimental and control groups. Achilles tendon defect model was created. That defect was repaired with a deep-frozen decellularized tendon allograft in the experimental group. In the control group, that defect was repaired with autologous tendon graft, the Achilles tendon that was removed to create the defect. The rats were killed and the tendon grafts were harvested 1, 2, 4 and 8 weeks postoperatively. HE staining was performed and the morphological changes of the tendon graft were observed. Image analyses based on immunohistochemical staining of collagen type Ⅰ and Ⅲ were performed, and biomechanics parameters including elastic modulus and ultimate failure load were tested in two groups. Results Expression levels of collagen type I and HI increased over time. In 1 and 2 weeks post-grafting, tendons in the control group had significantly higher levels of collagen expression than tendons in the experimental group （ P 〈 0.05）. There was no significant difference of collagen expression between the two groups in 4 and 8 weeks. The values of elastic modulus and ultimate failure load were greater in the control group than in the experimental group in 1 and 2 weeks postgrafting （ P 〈 0.05）, but there was no significant difference in 4 and 8 weeks. Conclusion The long-term results of deep-frozen decellularized tendon grafting are similar to those of autologous tendon grafting. Allografts treated with deep frozen decellulafization can be used as tendon grafts.