2,5-己二酮染毒对大鼠坐骨神经雪旺氏细胞中S100β的影响

Effects of 2,5-hexanedione on S100β of Schwann cells in rat sciatic nerves

目的观察2,5-己二酮(2,5-hexanedione,HD)染毒致中毒性周围神经病变大鼠坐骨神经雪旺氏细胞中S100β蛋白与mRNA表达变化。方法将9周龄SPF级Wistar雄性大鼠分为3组,每组23只。HD低剂量和高剂量组经腹腔注射染毒给予100 mg/kg和300 mg/kg HD,连续8周,每周5次;对照组给予等体积生理盐水。各组处死10只大鼠并分离坐骨神经,采用免疫组化方法检测S100β蛋白表达和实时定量聚合酶链式反应方法观察mRNA表达,另取3只大鼠分离坐骨神经用于电镜观察。其余30只大鼠停止染毒、自然恢复8周后取材。结果染毒8周后高剂量组动物后肢全部瘫痪,低剂量组动物步态异常如后肢肌力下降。电镜观察染毒组动物坐骨神经髓鞘的形态异常。低、高剂量组中S100β表达量分别为对照组的92%和79%,染毒终止、恢复8周后为149%(P<0.05)和119%。染毒8周时S100βmRNA表达水平均降低,为对照组的0.65倍(P<0.05)和0.56倍(P<0.05),染毒终止、恢复8周后分别为1.46倍和0.87倍。结论 HD染毒大鼠中毒性周围神经病变坐骨神经雪旺氏细胞中S100β蛋白和mRNA表达发生变化,S100β蛋白参与了中毒性周围神经病变发生。

OBJECTIVE To investigate the expression of S100β protein and mRNA of Schwann cells(SC) in sciatic nerves of 2,5-hexanedione(HD) intoxicated rats. METHODS Nine-week old SPF male Wistar rats were administered at daily dosing of 100 and 300 mg/kg by intraperitoneal injection for continuous 8 weeks(five times every week). Age-matched control rats received an equivalent volume of normal saline. Ten rats in each group were sacrificed and sciatic nerves were excised for S100β determination, with excised sciatic nerves from another three rats for morphological observation through electron microscope. At the end of the exposure, the other 8-week treated animals were allowed to naturally recover for 8 weeks and sciatic nerves were excised at the end of the test. S100β protein contents were determined by immunohistochemistry method, and mRNA expression was observed by real-time quantitative polymerase chain reaction(PCR). RESULTS HD intoxication with 300 mg/kg was associated with severe neurological deficits of paralysis in hindlimbs, accompanied with evident movement gait abnormalities for 100 mg/kg dosage. The morphological abnormalities in myelin sheath of sciatic nerves were observed through electron microscope after HD-exposure. The S100β contents in 100 mg/kg and 300 mg/kg groups remained relatively unaffected with 92% and 79% of the control respectively after HD-intoxication, and a increase to 149%(P<0.05) and 119% after a recovery of 8 weeks was accompanied with. As to S100β mRNA, HD-intoxication was associated with decreased expression to 0.65(P<0.05) and 0.56 times(P<0.05) of the control, and 1.46 and 0.87 times for 8-week recovery individually. CONCLUSION The S100β protein and mRNA levels were influenced by HD exposure, and the result suggested that S100β might be involved in HD-induced peripheral axonopathy.