对大鼠脑缺血再灌注后tTG表达的影响

目的   研究胱氨酸（Cystamine）对全脑缺血再灌注损伤后大鼠海马组织型转谷氨酰胺酶（tTG）表达的影响。方法    用四血管阻断法制作大鼠全脑缺血再灌注模型。将SD大鼠随机分为假手术组（n=8），全脑缺血组（n=48）及全脑缺血治疗组（n=48），全脑缺血组和全脑缺血治疗组按照缺血再灌注时间点的不同再将大鼠随机分为6h、12h、1d、3d、5d、7d六个亚组，每个亚组8只。全脑缺血治疗组大鼠给予Cystamine腹腔注射（0.15mg/g）,全脑缺血组和假手术组大鼠给予生理盐水腹腔注射。TUNEL染色法观察细胞凋亡水平的变化，免疫组织化学方法分析再灌注后不同时间点海马CA1区tTG表达水平的变化。另取52只大鼠随机分为假手术组（n=4）、全脑缺血组（n=24）及全脑缺血治疗组（n=24），全脑缺血组和全脑缺血治疗组按照不同时间点每个亚组4只，免疫印迹方法测定tTG的表达。结果   缺血组再灌注24h后TUNEL阳性细胞明显增加，1、3、5、7d亚组与假手术组差异有统计学意义（P<0.05）；治疗组与缺血组相比，在1、3、5、7d相应时间点亚组TUNEL阳性细胞数减少（P<0.05）。治疗组海马CA1区tTG平均阳性细胞数于全脑缺血后12h开始下降,3、5、7d亚组均明显低于缺血组（P<0.05）。治疗组海马tTG蛋白水平于缺血再灌注后1d开始降低，3、5和7d亚组显著低于缺血组（P<0.05）。结论   Cystamine可以降低大鼠全脑缺血再灌注后海马CA1区tTG的表达，从而对神经元细胞起到一定的保护作用。

Effect of Cystamine on the expression of tissue-type transglutaminase after global cerebral ischemia-reperfusion in rats

Objective    To observe the effect of Cystamine on the chronological expression of tissue-type transglutaminase after the hippocampal region of global cerebral ischemia-reperfusion injury in rats. Methods   The experimental global cerebral ischemia-reperfusion injury model was established by the method of 4-vessel occlusion.The Sprague-Dawley rats were randomly divided into sham-operated group (n=8), global cerebral ischemia group (n=48) and global cerebral ischemia treatment group(n=48) . Global cerebral ischemia group and global cerebral ischemia treatment group were divided into six subsets such as 6,12hour,1,3,5,7day according to the time point with 8 rats. Cystamine was injected intraperitoneally［0.15mg/(g·day)］10 minutes after cerebral ischemia for global cerebral ischemia treatment group. Saline was injected intraperitoneally for global cerebral ischemia group and sham operated group. Neurons apoptosis was detected by TUNEL technology and the expression of tTG was detected by Immunohistochemistry(SP)in the hippocampal CA1 region of different time points.The other 52 rats were randomly divided into sham-operated group(n=4) , global cerebral ischemia group(n=24) and global cerebral ischemia treatment group (n=24). Global cerebral ischemia group and global cerebral ischemia treatment group were divided into six subsets according tothe time point with 4 rats.The expression of tTG was detected by Western blotting. Results    About 24h after ischemia reperfusion injury ,the positive cells of TUNEL staining were significantly increased. Compared to the sham-operated group, the positive cells of TUNEL at the subset 1, 3, 5, 7day after global cerebral ischemia group were significantly increased（P<0.05）.The number of apoptotic cells in subset 1, 3, 5, 7day of global cerebral ischemia treatment group were significantly less than that of global cerebral ischemia group （P<0.05）. In global cerebral ischemia treatment group, tTG immunopositive cells began to decrease in the CA1 region of hippocampus in subset 12hour time point,and significantly decreased in 3, 5, 7day subset of global cerebral ischemia group（P<0.05）. In global cerebral ischemia treatment group, tTG protein level began to increase 1 days after ischemia-reperfusion, and significantly decreased in 3, 5, 7day subset of global cerebral ischemia group（P<0.05）. Conclusion    Cystamine can reduce the expression of tTG after the hippocampal CA1 region of global cerebral ischemia reperfusion injury in rats, which might be the mechanism of protecting ischemic injury of neurons.