摘要
目的 观察多聚ADP-核糖聚合酶(PARP)与钙依赖性蛋白激酶(Calpain)在脑缺血再灌流损伤中的表达以及凋亡的形态学特征,探讨PARP和Calpain在细胞凋亡中的作用。
方法 成年健康雌性Wistar36只大鼠,应用线栓法建立大脑中动脉闭塞再灌流模型(MCAO)。随机分为假手术组和实验组。用原位TUNEL和原位杂交技术探求脑缺血后细胞凋亡发生的意义和动力学各方面的变化以及PARP和Calpain在大鼠脑缺血再灌流不同时间点的表达。
结果 缺血再灌流组凋亡细胞主要位于缺血周围区,坏死细胞主要集中于缺血中心区,再灌流2h即出现凋亡细胞,随着再灌流时间的延长逐渐增多,至24h达高峰,2d开始下降,至14d时仍高于假手术组,各相邻时间点比较差异显著(P<0.05)。缺血中心区凋亡细胞数量较少,其变化规律与缺血周围区相似,除再灌流2h,7d,14d外,其余各时间点无显著性差异(P>0.05)。PARP的表达在脑缺血再灌流2h、6h、12h、2d、3d、7d后神经元数皮质区与假手术组比较,相差非常显著(P<0.01)。再灌流后2h明显升高,6h达高峰,然后下降,14d降至最低点,与假手术组相比也有统计学意义(p<0.05)。纹状体与假手术组比较,再灌流2h、6h、12h、2d、3d、7d相差非常显著(P<0.01)。再灌流后2h已达高峰,然后逐渐下降,14d降至最低点,不过与假手术组相比仍有统计学意义(p<0.05)Calpain的表达在脑缺血1h再灌流2h、6h、12h、2d、3d、7d后神经元数在皮质区与假手术组比较,相差非常显著(P<0.01)。再灌流后2h已达高峰,6h下降,12h又明显升高,然后逐渐下降,14d降至最低点。但14d与假手术组相比,有统计学意义(p<0.05)。纹状体与假手术组比较,相差非常显著(P<0.01).再灌流后2h明显升高,6h反而下降,12h又升高至高峰,然后逐渐下降,14d降至最低点。但14d与假手术组相比,有统计学意义(p<0.05)。
结论 脑缺血后细胞凋亡主要位于缺血周围区,PARP与Calpain在脑缺血细胞凋亡中起重要的作用。PARP与Calpain抑制剂对缺血性脑损伤的防治具有非常重要的意义。
Aim The study is to explore the expression of poly (ADP-ribose) polymerase (PARP) and Calpain in focal cerebral ischemia with reperfusion injury and observe morphological features of apoptotic cells and the role of PARP and Calpain in apoptosis.
Methods 36 adult female Wistar rats were subjected to middle cerebral artery occlusion (MCAO) and different time of reperfiision. Rats were randomly divided into MCAO groups and sham group that were same as operation, but no MCAO. To explore the implication and the kinetics of such event in apoptosis induced insult induced by MCAO in situ TUNEL technic. To observe the expression of PARP and Calpain at the different time points and then assess their function in apoptosis induced by MCAO in situ hybridization technic
Results Apoptotic cells lie in the boundary zone to the ischemic core. The number of apoptotic cells in the ischemic core was less than ischemic penumbra (p<0.05) except for 2 h, 7 d, 14 d. Situ hybridization demonstrated the evident expression of PARP at 2 h. The peak of PARP was first detected at 2 h in the corpus striatum and then cerebral cortex at 6 h . With increasing length of survival, the expression of PARP began to decrease, then dropped a very low level at 14 d. But there are difference between MCAO group and sham control (p<0.05). Situ hybridization demonstrated the evident expression of Calpain in the cerebral cortex and corpus striatum at 2 h. The study was detected a bimodal pattern of Calpain with an initial increase at 2 h followed by a more prominent secondary increase at 12 h after reperfusion. After 24 h Calpain began to decrease, then dropped a very low level at 14 d. But there are difference between MCAO group and sham control (p<0.05).
Conclusion Apoptosis lie in the boundary zone to the ischemic core. PARP and Calpain play an important role in apoptosis. The inhibition of PARP and Calpain can prevent and cure cerebral ischemic damage.
引文
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