摘要目的 研究缺血性脑卒中对犬肠黏膜屏障功能的影响以及细胞凋亡和紧密连接蛋白在其中的可能机制.方法 杂犬20只,按随机数字表法分为梗死组和假手术组,每组10只.梗死组采用双硅柱置入法制作缺血性脑卒中模型,假手术组动物不置入栓子,其他同梗死组.光镜下观察肠黏膜形态;免疫组织化学法分析肠黏膜紧密连接蛋白闭锁蛋白和闭锁小带蛋白1的表达;采用TdT介导的dUTP缺口末端标记技术检测肠上皮细胞凋亡.结果 梗死组动物均形成脑梗死.和假手术组相比,梗死组紧密连接蛋白闭锁蛋白和闭锁小带蛋白1表达均明显降低(闭锁蛋白平均光密度值:0.20±0.01比0.22±0.01,P=0.007;闭锁小带蛋白1平均光密度值:0.20±0.01比0.22±0.02,P=0.008);梗死组凋亡指数明显增高(29.04 ±3.79比6.44±1.24,P=0.002);闭锁蛋白与闭锁小带蛋白1呈正相关(R=0.71,P=0.02);凋亡指数与闭锁蛋白和闭锁小带蛋白1均呈负相关(R=-0.91,P=0.00;R=-0.77,P=0.01).光镜下梗死组存在小肠病理损伤,假手术组小肠结构正常.结论 缺血性脑卒中时,肠道屏障功能发生损害.紧密连接蛋白闭锁蛋白和闭锁小带蛋白1表达降低,从而导致紧密连接破坏.肠黏膜细胞凋亡上调是肠屏障障碍的细胞学基础,凋亡是缺血性脑卒中时肠上皮细胞死亡的重要形式.

abstractsObjective To explore the impact of ischemic stroke on intestinal barrier changes in dogs.Methods Totally 20 mongrel dogs were divided into 2 groups by random number table with 10 in each.Double silicone cylinders measuring 1.1 mm in diameter and 8 mm in length were placed into their internal carotid arteries in all dogs of group A.Group B served as a control group and received sham operation.Light microscopy was performed for morphological measurement of intestinal epithelial cell.Immunohistochemistry was used to analysis the changes of protein zonula occludens-1(ZO-1)localizing at tight junction of intestinal epithelial cells.Results Ischemic stroke was confirmed by cranial CT scanning in all dogs of group A.Compared with the test results in group B,the occludin and Zo-1 protein levels in group A were significantly lower than those in group B(occludin:0.20 ±0.01 vs 0.22 ±0.01,P =0.007; ZO-1:0.20 ±0.01 vs 0.22 ±0.02,P =0.008).The apoptotic index in group A was significantly higher than in group B(29.04 ± 3.79 vs 6.44 ± 1.24,P =0.002).There was a positive correlation between occludin and ZO-1(R =0.71,P =0.02),and the apoptotic index was negatively correlated with levels of occludin,ZO-1(R =-0.91,P =0.00; R =-0.77,P =0.01).Light microscopy showed that the dogs in group A had intestinal mucousal injuries while no obvious change was detected in group B.Conclusions Dogs with ischemic stroke tend to develop intestinal barrier dysfunction,during which the destruction of tight junction plays a key role.The up-regulated apoptosis of intestinal epithelial cell constitutes one of the cellular bases of intestine injury.