乙醛脱氢酶在大鼠脑缺血再灌注损伤中的表达及意义

Expression and significance of ALDH-2 in cerebral ischemia-reperfusion of rats

目的探讨大鼠脑缺血再灌注损伤后脑组织乙醛脱氢酶(ALDH-2)的表达及意义。方法雄性SD大鼠随机分为假手术(S)组、脑缺血-再灌注损伤(脑I/R)组。分别于缺血再灌注后6、12、24和72 h采用实时荧光RT-PCR法检测各组脑组织ALDH-2 mRNA及Caspase-3 mRNA的表达。末端原位标记检测神经元细胞的凋亡。结果与假手术组比较,脑I/R损伤再灌注后ALDH-2 mRNA表达明显下降,且随着I/R时间的延长其表达逐渐降低,并于72 h达到最低值(P<0.05);Caspase-3 mRNA在假手术组中有少许表达,而脑I/R损伤后表达明显升高,并于12 h升高达到峰值,随后伴随I/R时间的延长其表达逐渐下降,但其表达仍较假手术组水平高(P<0.05);假手术组中未见明显的TUNEL阳性细胞,而大鼠脑I/R损伤后,在各时间点均可见明显的TUNEL阳性细胞,并在72 h时凋亡最为明显;脑缺血再灌注组大鼠组织ALDH-2 mRNA表达与Caspase-3 mRNA表达呈负相关(r=-0.32,P<0.05)。结论大鼠脑I/R损伤后,脑组织ALDH-2 mRNA的表达持续下调的机制可能与细胞凋亡的发生有关。

【Objective】To investigate the expression and significance of ALDH-2 in brain tissue after cerebral ischemia and reperfusion. 【Methods】Forty healthy male SD were randomly divided into two groups： sham control group, cerebral ischemia/reperfusion group. The mRNA expression of ALDH-2 and Caspase-3 were determined by real-time PCR in 6, 12, 48, 72 h after cerebral ischemia and reperfusion, and the apoptosis was detected by terminal dexynucleotidyl transferase（TdT）-mediated dUTP nick end labeling（TUNEL）. 【Result】Compared with sham control group, the mRNA expression of ALDH-2 significantly decreased after cerebral ischmia, and gradually decreasedaccompanied with the prolonging of the reperfusion time, then peaked at 72 h（P〈0.05）. There were only little Caspase-3 mRNA expression in the sham control group rats, however, the expression of Caspase-3 increased gradually after cerebral ischmia, peaked at 12 h（P〈0.05）, and then gradually decreased, but it was still higher than that in sham control group（P〈0.05）. We also found that the TUNEL positive cell were scarcely detected in the sham control group, while the TUNEL positive cell were obviously detected in the cerebral ischemia whenever reperfusion,and more apoptosis cells were examined at 72 h. Furtherly, we found that the ALDH-2 mRNA expression was associated negatively with Caspase-3 mRNA expression（r =-0.32,P〈0.05）.【Conclusion】ALDH-2 mRNA expression was down-regulated in cerebral ischemia/reperfusion, and the mechanism maybe was related with apoptosis.