甲基强的松龙对大鼠急性脊髓损伤模型wnt/β-catenin信号通路相关蛋白表达的影响

Effect of methylprednisolone on wnt/β-catenin signaling pathway-related protein expressionin in rat model of acute spinal cord injury

目的:研究甲基强的松龙对急性脊髓损伤(SCI)大鼠模型wnt/β-catenin信号通路相关蛋白表达的影响。方法:SD大鼠48只随机分为,甲基强的松龙处理组(Meth)、生理盐水处理组(Salin)和假手术组(Sham,仅进行椎板切除术)。Meth(甲基强的松龙,30 mg/kg)和Saline(生理盐水,等量)组通过Allens法建立急性SCI模型后经尾静脉立即注射,并在SCI后的1 d和2 d相同时间点各注射1次。SCI模型建立后用尼氏染色(Nissl)观察神经细胞变化,用Western Blot检测wnt/β-catenin信号通路相关蛋白β-catenin和GSK-3β的表达,用免疫荧光技术观察凋亡相关蛋白caspase-3和caspase-6表达,进行统计学处理。结果:实验组SCI后7 d,尼氏染色观察到Meth组前角运动神经元形态和数量得到明显改善(P<0.01),同时对损伤区域修复有明显促进作用。SCI后3 d和7 d,Western Blot显示β-catenin表达水平明显(P<0.05),而GSK-3β蛋白表达则降低(P<0.05);免疫荧光观察到,甲基强的松龙处理组凋亡活动被明显抑制,表现为凋亡蛋白caspase-3和caspase-6降低(P<0.01)。结论:结果表明,甲基强的松龙可能通过激活wnt/β-catenin信号通路影响一些相关蛋白表达,从而抑制大鼠急性SCI神经细胞的凋亡和促进运动功能恢复。

Objective： To study the effects of methylprednisolone on wnt/β-catenin signaling pathway related protein expression in the rat model of acute spinal cord injury（ SCI）. Methods： Forty eight SD rats were randomly divided into methylprednisolone treatment（ Meth）,normal saline and sham operation group（ Sham,only laminectomy）. The methylprednisolone and saline were administrated by the tail intravenous injection（ 30 mg / kg） after SCI and then once daily for 2 days. After establishing the SCI model with the modified by Allen＇s method,neural cell changes were observed with the Nissl staining,and expressions of wnt /β-catenin signaling pathway associated protein β-catenin and GSK-3 were measured by Western Blot,and the apoptosis related proteins of caspase-3 and caspase-6 were determined by immunofluorescence technique. The results were statistically analyzed. Results： At the 7th day after rat SCI,the morphology and number of the anterior horn motor neurons were observed to be significantly improved（ P〈0. 01） observed by Nissl staining in Meth group,and the damage zone was repaired. At the 3rd day and the 7th day,β-catenin expression was clearly identified by Western Blot（ P〈0. 05）,GSK-3βprotein expression was decreased（ P〈0. 05）. Immunofluorescence staining showed that,apoptotic activity was obviously inhibited,the expression of caspase-3 and caspase-6 significantly decreased in methylprednisolone-treated rats（ P〈0. 01）. Conclusion： The results showed that through activatis wnt / β-catenin signaling pathway,methyprednisolne might inhibit the apoptosis of menronal cells and promote the recovery of motor function in a rat model of acute SCI.