脊髓缺血再灌注损伤对大鼠水通道蛋白4表达的影响

Expression of AQP4 on spinal cord ischemia-reperfusion injury of rats

目的:在整体水平研究脊髓缺血再灌注损伤对大鼠水通道蛋白4表达水平的影响。方法:SD大鼠72只随机分为空白组、假手术组和SCII组,每组24只。建立大鼠脊髓缺血再灌注损伤模型,并于1、3、5、7天四个时间点分别处死6只。BBB评分评价神经功能,Western blot和免疫荧光方法检测AQP4的表达情况。结果:空白对照组和假手术组在不同时间点的BBB评分均为21分,SCII组的BBB评分在1天时最低,随时间推移逐渐增加,3天明显优于1天(P<0.05),5天明显优于3天(P<0.05),5天明显优于7天(P<0.05)。Western blot在34 kD及43 kD分子量处可见特异性条带,SCII组早期AQP4的表达水平显著下降,即在1、3、5、7天四个时间点AQP4的表达显著低于空白对照组和假手术组,但呈逐渐增加趋势;在7天仍显著低于正常空白组和假手术组(P<0.05)。免疫荧光检测AQP4的表达变化趋势与Western blot的检测结果相似。结论:SCII存在AQP4低表达,这可能是造成SCII神经功能障碍的重要原因。

Objective： To explore the effect of spinal cord ischemia-reperfusion injury（SCII） on aquqporin4（AQP4） in a SCII rat model.Methods： Seventy-two Sprague-Dawley（SD） rats were randomly divided into three groups with twenty-four rats in each group.The groups were： blank group;sham operation;and SCII group at 1,3,5,or 7 days after reperfusion started,six rats of every group were then killed.BBB scoring system to evaluate the nerve function,and the expression of AQP4 was determined by Western blot and immunofluorescence.Results：At different time,the BBB score of blank group and sham operation have no fluctuations,and has no significant differences.In SCII group,the BBB score has a dynamic change,with a significant increasing at 1~7 d,3 days significantly better than 1 day（P0.05）,5 days significantly better than 3 days（P0.05）,5 days significantly better than 7 days（P0.05）.Western blot specific bands of AQP4 visible at a molecular weight of 34 kD and 43 kD,the AQP4 protein production of SCII was markedly lower than those of blank group at 1,3,5 and 7 d,respectively.The AQP4 level increased gradually,but still lower than that of blank group and sham operation group in 7 days（P 0.05）.At the same time,the AQP4 measured also by immunofluorescence,the expression of AQP4 is similar to the AQP4 level measured by Western blot（P0.05）.Conclusion：The AQP4 level was significantly decreased in the SCII,indicating that the low expression of AQP4 might play an important role in the mechanisms of SCII neurological dysfunction.