尿激酶型纤溶酶原激活剂对大鼠面神经损伤修复的影响

目的 :探讨尿激酶型纤溶酶原激活剂 (uPA)在神经再生微环境中的作用机制 ,观察uPA对面神经断伤吻合后神经再生修复的影响。方法 :将 2 4只SD大鼠随机分为uPA组和对照组 ,建立大鼠面神经断伤修复模型 ,uPA组术后连续 5d腹部皮下注射uPA ,每天 3次 ,每次 5 0 0 0U/kg ,对照组注射等体积生理盐水。术后 1,7,14 ,2 1,4 2 ,84d取吻合处远侧段面神经 ,采用形态学、免疫组织化学和图像分析技术 ,观察分析两组中神经纤维的等效直径、周长和面积参数以及纤维连结蛋白 (fibronectin ,FN)和层粘连蛋白 (laminin ,LN)伤后早期的表达变化。结果 :术后 2 1,4 2d时uPA组新生神经纤维髓鞘面积和 4 2d时等效直径均较对照组恢复好 (P <0 .0 5 )。FN在术后表达逐渐增强 ,14 ,2 1d时较对照组明显增多 (P <0 .0 5 )。两组中LN术后表达均减少 ,随再生过程而逐渐增多 ,组间差别无统计学意义。结论 :面神经断伤吻合后应用uPA可降解纤维蛋白 ,使FN表达上调 ,有利于改善神经再生后的微环境 ,提高新生神经纤维的再生修复效果

Effect of urokinase plasminogen activator on injuried facial nerve of rats

Objective:To observe the effect of uPA on nerve regeneration and the expression of fibronectin and laminin after the facial nerve were transected and anastomosed,and to explore the mechanism of uPA in the microenvironment of nerve regeneration.Method:Twenty four SD rats were randomly divided into two groups: uPA group and control group. Every rat's extracranial facial were transected and anastomosed. Then uPA were injected at the belly of rat subcutaneously for five days in uPA group, three times one day, 5 000 U/kg one time.Equal volume saline were injected in control models at the same site and the same time.At 1,7,21,42,84 day of post-operation, the diameter,perimeter,myelin sheath area of fibers and the expression of fibronectin and laminin in early phase of post-operation were measured by using morphometry,immunochemistry and the image analysis.Result:After operation, myelin sheath area at 21,42 day and diameter of new regenerated fiber at 42 day in uPA group were better than those in control group(P< 0.05). The expression of fibronectin elevated gradually after operation, and it expressed more than that of control group at 14 and 21 day (P< 0.05). The expression of laminin decreased after operation, then elevated with the progress of nerve regeneration and showed no significant difference between two groups.Conclusion:The uPA can promote the fibrin degradation and upregulate the fibronectin expression when applicating in rat model, which benefit to improve the microenvironment and enhance facial nerve regeneration.