正己烷中毒大鼠坐骨神经病理改变和Sarm1蛋白表达关系

Discussion on the relationship between pathological changes of sciatic nerve and Sarm1 protein expression in rats with n-hexane poisoning

目的探讨正己烷对大鼠周围神经产生的毒性作用对周围神经主动坏死现象的产生提供潜在证据。方法于2023年5月,选择体重为200~220 g的36只SPF级SD雄性大鼠,随机分成4组,每组9只,对照组、低、中、高剂量组分别予生理盐水、不同剂量正己烷(168、675、2700 mg/kg)连续6周(5 d/周)灌胃。各组分别于第2、4、6周处死3只大鼠,取大鼠脊髓至坐骨神经组织,破碎、离心并取上清液进行聚丙烯酰胺凝胶电泳(SDS-PAGE)分离蛋白,用Western blot法检测Toll白介素受体基序蛋白1(Sarm1)蛋白表达水平,并与内参蛋白β-Actin显色条带进行灰度分析,以二者灰度比值分析Sarm1蛋白表达情况。第6周各组大鼠坐骨神经光镜、电镜切片进行观察。结果光镜示轴突数量明显减少;电镜示髓鞘病变主要为局部崩解、变形、厚薄不一,轴突腔面变形变小,神经束膜内轴突呈退行、减少表现,高剂量部分轴索呈华勒氏退行性病理表现。各组大鼠染毒Sarm1与内参蛋白显色条带灰度比值第2周无明显变化,第4周高剂量组为1.47,第6周中剂量组和高剂量组分别为1.51、1.89,均为明显表达。结论正己烷中毒大鼠的坐骨神经病理表现中观察到华勒氏退行性病变现象,同时Sarm1蛋白表达水平上升。

ObjectiveTo explore the potential evidence of active peripheral nerve necrosis when n-hexane produces toxic effects on peripheral nerves.MethodsIn May 2023,36 SPF grade SD male rats with a body weight of 200-220 g were divided into 4 groups with 9 rats in each group and given normal saline and different doses of n-hexane(168,675,2700 mg/kg)by gavage for 6 consecutive weeks(5 days/week).Three rats in each group were killed at the 2nd,4th and 6th week,respectively.The spinal cord to sciatic nerve tissue was broken and the supernatant was extracted for SDS-PAGE protein isolation.The expression level of Sarm1 protein was analyzed with theβ-Actin color strip of internal reference protein by Western blot.The expression of Sarm1 protein was analyzed by the gray ratio of the two.At the 6th week,the sciatic nerve sections of the each group were observed by light microscope and electron microscope.ResultsThe number of axons was obviously reduced by light microscopy.According to electron microscope,myelin lesions were mainly local disintegration,deformation,and different thickness.The deformation of axonal surface became smaller.The axons in the nerve bundle membrane showed degeneration and reduction.The gray ratio of Sarm1 protein and internal reference protein bands in each group had no significant change at the second week of exposure,and the ratio of SARM1 protein to internal reference protein bands was 1.47 in the high dose group at the fourth week,and 1.51 and 1.89 in the middle and high dose group at the sixth week,respectively.ConclusionWaller's degeneration was observed in sciatic neuropathologic manifestations of n-hexane-poisoned rats,and the expression level of Sarm1 protein increased.