脊髓缺血再灌注损伤后μ-Calpain mRNA及蛋白的表达

Expressions of μ-Calpain mRNA and protein after spinal cord ischemia-reperfusion injury

目的探讨钙调蛋白μ-Calpain在脊髓缺血再灌注损伤中的表达及意义。方法建立成年SD大鼠缺血再灌注损伤模型,利用实时荧光定量PCR技术及Western-blot技术检测模型建立后2 h、6 h、12 h、24 h、48 h及72 hμ-Calpain mRNA及蛋白的表达情况。利用Western-blot技术检测μ-Calpain特异性底物α-II Spectrin的降解,并与对照组进行对比。结果与对照组相比,脊髓缺血再灌注损伤模型建立后2 h,损伤段脊髓μ-Calpain mRNA的表达开始增高,但差异无统计学意义,12 h后明显增高,差异有统计学意义(P<0.05),48 h达峰值(P<0.001),72 h后仍有μ-Calpain mRNA的表达且高于对照组,差异有统计学意义(P<0.05)。模型建立后2 h损伤段脊髓μ-Calpain蛋白增高,48 h达峰值(P<0.001),72 h后μ-Calpain蛋白仍高于对照组,差异有统计学意义(P<0.05)。α-II Spectrin降解在模型建立后2 h即出现,但差异无统计学意义(P>0.05),72 h后有少量α-ⅡSpectrin残留。结论脊髓缺血再灌注损伤模型建立后,μ-CalpainmRNA及蛋白表达增加,对其特异性底物α-II Specrin进行降解,参与了脊髓缺血再灌注损伤的病理过程。

Objective To explore the expressions and signiifcance ofμ-Calpain after spinal cord ischemia-reperfusion injury. Methods An adult Sprague-Dawley （ SD ） rat model of spinal cord ischemia-reperfusion injury was established. Quantitative real-time lfuroscent polymerase chin reaction （ PCR ） and Western-blot technique were used to detect the expressions of mRNA and protein ofμ-Calpain at 2 h, 6 h, 12 h, 24 h, 48 h and 72 h after the model was established. The degradation ofα-II specrin of the speciifc substrate of ofμ-Calpain was detected by Western-blot technique, and the results were compared with that of the control group. Results The expressions ofμ-Calpain mRNA of the injured spinal cord began to increase at 2 h after the model was established, but there were no statistically significant differences. The expressions were obviously increased at 12 h, and there were statistically significant differences （ P〈0.05 ）. The peak was reached at 48 h after the model was established （ P〈0.001 ）. The expressions ofμ-Calpain mRNA remained at a higher level at 72 h when compared with that of the control group, and there were statistically signiifcant differences （ P〈0.05 ）. The expressions ofμ-Calpain protein of the injured spinal cord began to increase at 2 h after the model was established, and the peak was reached at 48 h （ P〈0.001 ）. The expressions ofμ-Calpain protein remained at a higher level at 72 h after the model was established when compared with that of the control group, and there were statistically signiifcant differences （ P〈0.05 ）. Theα-II spectrin began to degenerate at 2 h after the model was established, but there were no statistically signiifcant differences. There were still someα-II spectrin remains at 72 h. Conclusions The expressions ofμ-Calpain mRNA and protein are increased after the spinal cord ischemia-reperfusion injury model is established, and meanwhile theα-II specrin of its speciifc substrate begins to degenerate. Theμ-Calpain is involved in the pathological course of spinal cord ischemia-reperfusion injury.