暂时阻断夹对局部血管壁损伤的电镜研究

Study through electron microscope of focal vascular injury caused by temporary clipping

目的 探导暂时阻断夹夹闭颈内动脉、大脑中动脉不同时限对局部血管壁损伤的情况。方法 将SD大鼠64只随机分为颈内动脉和大脑中动脉两组 ,每组又随机分为四个亚组。手术暴露颈内动脉或大脑中动脉后 ,用动脉暂时阻断夹夹闭颈内动脉或大脑中动脉 ,分别阻断 0 .5h ,1h ,2h ,2 .5h后 ,再灌流至 2 4h ,然后处死动物。取夹闭段动脉 ,用电镜观察血管壁超微结构改变。结果 夹闭 3 0min组 ,偶见内皮细胞浆内出现空泡 ,细微处可见平滑肌细胞粗面内质网扩张 ;夹闭 60min组可见平滑肌细胞线粒体轻度肿胀 ,肌层稍变厚 ,其间偶见有新分泌形成的胶原蛋白或 /和弹性蛋白 ,内皮细胞浆内出现散在空泡 ,有少许疏松的细胞间质 ;夹闭 12 0min组见肌层增厚明显 ,平滑肌线粒体肿胀 ,中膜平滑肌伸出较长的突起 ,穿越附近的平滑肌细胞及内弹力层而达内皮下层 ,其细胞突起周围则见有较多新分泌形成的胶原蛋白或/和弹性蛋白 ;部分可见内皮细胞层与内弹力膜层分离 ;夹闭 15 0min组内皮细胞核出现固缩 ,部分内皮细胞层脱落。结论 夹闭 60min是血管壁能耐受的最大极限 ,如进一步延长夹闭时间 ,可引起局部血管壁的损伤和管腔的狭窄 ,以及内皮细胞的脱落形成栓子 。

Objective To explore the focal vascular injury caused by temporary clipping.Methods SD rats were randomly divided into two groups,with the one group of intra-carotid artery(ICA) and the other of middle cerebral artery(MCA).Each group was divided again randomly into control subgroup and ischemia subgroup.After being exposed through operation,the MCA or ICA was temporarily clipped for 0.5h,1h,2h,and 2.5h respectively before reperfusion to 24h before execution.The clipped segment was taken,observed and photoed through electron microscope.Results In the 0.5h subgroup,bubbles were occasionally seen in the endotheliocyte plasm,the coarse endoplasmic reticulum could be seen dilating when taking a closer look.In the 1h subgroup,the cytoplasm of these smooth muscular contained slightly swollen mitochondrin;the muscle layer thickened a little,among which newly-formed collagen or elastin may be seen taking shape,with some loose CM;scattered bubbles appeared in the endotheliocyte plasm.In the 2h subgroup,the muscle layer thickened considerably,and mitochondrin swelled in the smooth muscle.Media of smooth muscle had protruding part which penetrated the nearby smooth muscle cells and internal elastic lamina to reach under the endothelium with the newly-formed collagen or elastin around;in some cases,the endothelium was separated from the internal elastic lamina.In the 2.5h group,karyon of endothelium appeared contraction and part of the endothelium had peeled off.Conclusions The maximum time span of clipping the vessle wall can endure should be 60min.The prolonged clipping time could cause the local vascular cavity stenosis and closure,thus leading to irreversible cerebral ischemia or injury.