甲壳素涂层PGLA神经导管修复兔面神经缺损的实验研究

Experimental study of rabbit gacial nerve regeneration through poly(L-lactide-co-glycolide) verve conduit coated with chitin

目的:探讨甲壳素涂层PGLA神经导管修复兔面神经缺损的效果。方法:成年雄性新西兰兔24只,无菌条件下切断双侧面神经下颊支,制成15mm的兔面神经下颊支缺损模型。左侧用甲壳素涂层聚丙交脂-乙交脂共聚物[poly(L-lactide-co-glycolide),PGLA]神经导管修复;右侧用翻转自体神经修复作为对照。术后5周、10周和14周行大体观察、电生理检查、组织学、电镜观察评价修复效果。结果:术后5周观察到神经导管中有新生轴索通过,再生神经发育不成熟;右侧自体神经修复近段有髓神经纤维均匀疏散分布,远段未见明显再生神经束形成。术后14周左侧再生神经已通过神经导管长入远端,电生理检查结果表明自体神经修复侧再生神经质量优于神经导管修复侧,差异有统计学意义(P<0.01)。自体神经修复再生纤维密度优于神经导管修复侧,差异有统计学意义(P<0.01),但自体神经修复侧近段神经髓鞘部分空泡样变性及脱髓鞘改变,远段再生神经纤维束形成少,面肌联带运动程度较导管修复侧严重。结论:甲壳素涂层PGLA神经导管能有效修复周围神经缺损,有望替代自体神经移植。

Objective To evaluate the result of using poly （L-lactide-co-glycolide ,PGLA） nerve conduit coated with chitin to repair rabbit facial nerve defect. Methods Twenty-four male adult rabbits were made the model of 15mm gap on buccal branch of the facial nerve under sterile condition. PGLA nerve conduit coated with chitin as experimental side to repair the left gap of facial nerve, and autologous nerve were grafted into the right gap as control side. The nerve regeneration was evaluated with electrophysiological and histological examination and morphometric analysis. Results Five weeks after the operation, there were new regenerated immature fibers in PGLA nerve conduit coated with chitin, there were myelinated fibers equably distributed and rarely new generated nerve fibers in distal parts of the right autograph. Fourteen weeks after the operation, the regenerated nerve fibers were seen to have bridged the left gap. There were significant difference in electrical impulse conduction velocity through the neural regenerates between the experimental and control sides （P〈0.01）. There were significant difference of nerve fiber density in the left gap from those in the right gap （P〈0.01） , but there were degenerative changes such as vacuoles in sheaths and myelin separation in proximal and few new regenerated nerve fibers in distal parts of the right sides. Conclusion PGLA nerve conduit coated with chitin offers a possible substitute for the repair of peripheral nerve defect.