大鼠脊髓损伤后局部应用聚乙二醇的抗神经纤维溃变研究

目的:探讨大鼠脊髓损伤后局部应用聚乙二醇(polyethylene glycol,PEG)的抗神经纤维溃变作用。方法:选取健康雄性Wistar大鼠,所有动物随机分为对照组和PEG治疗组。各组动物制作脊髓横断损伤模型。PEG治疗组大鼠在脊髓横断后,蛛网膜下腔立即注射PEG。对照组大鼠用生理盐水代替PEG,其余步骤相同。各组大鼠存活1、2、3 d后处死取材。标本切片后分别进行Massons染色和免疫荧光染色,比较各组切片每个高倍视野内的神经纤维溃变轴索球数目。其余动物麻醉后取出新鲜脊髓标本,制成匀浆后用免疫印迹法测定脊髓组织内钙蛋白酶(m-calpain)和神经丝蛋白(neurofilement,NF-200)降解产物的相对含量。结果:(1)对照组脊髓损伤部位大量炎症细胞浸润,组织坏死严重,损伤近侧端的轴索球明显多于PEG治疗组;PEG治疗组炎症反应较轻,组织坏死不明显,轴索球数目少于对照组。(2)PEG治疗组脊髓组织内m-calpain以及NF降解产物的含量均显著低于对照组。结论:大鼠脊髓损伤早期局部应用PEG可以有效减轻神经纤维的溃变。

A study on anti-nerve fiber degeneration with topical application of polyethylene glycol after spinal cord injury in rats

Objective: To investigate the role of polyethylene glycol(PEG) in anti-nerve fiber degeneration after spinal cord injury in rats.Methods: All healthy male Wistar rats were randomly divided into 2 groups: control group and PEG treatment group.The spinal cord transection was performed on all the rats.Each rat in PEG treatment group were immediately given PEG after spinal cord transection.In control group,PEG was replaced by normal saline,the remaining steps were the same.The rats were sacrificed after 1,2,or 3 days.After sectioning,Massins staining and immunofluorescence staining were performed,respectively.The number of degenerated axonal spheroids were counted in high power field and statistical analysis was performed.Some of the specimens were made into homogenate for Western blot to detect the relative amount of m-calpain and neurofiament(NF).Results:(1)The axonal spheroids of the control group were significantly more than that of PEG treatment group.Necrosis near the site of injury was more serious in the control group,and there were more inflammatory cells in control group than that in PEG treatment group.(2)The protein contents of m-calpain and degenerated production of NF were lower in PEG treatment group than in control group.Conclusion: Topical application of PEG at the early stage after spinal cord injury can effectively protect the axons from degeneration.