慢性脑缺血痴呆大鼠神经细胞凋亡的研究

Study on neural apoptosis in chronic ischemia-induced vascular dementia rats

目的:探讨细胞凋亡在慢性脑缺血导致大鼠痴呆中的作用。方法:Wister大鼠100只,雌雄各半,体质量350～400g。结扎大鼠双侧颈总动脉制备慢性脑确血致痴呆大鼠(vasculardementia,VD)模型;应用脱氧尿嘧啶缺口末端标记法(TUNEL)染色、流式细胞术及琼脂糖凝胶电泳方法检测VD大鼠的脑神经细胞凋亡情况。结果:流式细胞术检查发现额叶、海马在双侧颈总动脉结扎1周时细胞凋亡率分别为8.18%,21.92%;纹状体区2周时细胞凋亡率最高为9.22%,均明显高于对照组的2.84%,3.72%,2.18%(P<0.01),以后均逐渐下降。脑缺血一两周时TUNEL染色及额叶、海马及尾状核神经细胞凋亡明显高于对照组,4周以后与对照组差别不明显。琼脂糖凝胶电泳未见典型的细胞凋亡“梯形条带”。结论:神经细胞凋亡在大鼠双侧颈总动脉结扎后早期明显,晚期无明显改变。

AIM:To study the effect of neural apoptosis in chronic ischemia-induced vascu lar dementia (VD) rats. METHODS:One hundred Wistar rats weighing 350-400 g were randomly divided into control group and ischemic groups of 1, 2, 4, 8, 12 and 16 weeks postoperativel y. The bilateral common carotid arteries of the experimental rats were ligated s o as to construct a model of VD rat. Terminal dUTP nick and labeling (TUNEL), fl ow cytometry (FCM) and agarose gel electrophoresis were used to study the neural apoptosis in VD rats. RESULTS:FCM showed the apoptosis rates of the ischemic group increased to 8.18 %and 21.92%respectively in the frontal lobe and hippocampus at 1 week after op eration, while that reached the peak (9.22%)in corpus striatum at 2 weeks after operation, all of which were significantly higher those of the control group (2 .84%, 3.72%and 2.18%, respectively)(P< 0.01). TUNEL showed the apoptosis of t he ischemic group increased significantly at 1-2 weeks after operation, which w as higher than that of the control group, and then returned to the control level at 4 weeks postoperatively. No laddered DNA fragments were observed by agarose gel electrophoresis.