大鼠小肠缺血再灌注对视网膜的影响

Effects of intestinal ischemia-reperfusion on retina in rats

目的:探讨大鼠小肠缺血再灌注对视网膜的影响。方法:16只健康清洁Wistar大鼠随机分为2组,每组8只。对照组(C组):仅分离肠系膜上动脉(SMA),不夹闭;缺血组(I组):分离SMA并夹闭1h,再灌注2h。两组动物均下腔静脉微量输液泵持续输注0.9%生理盐水10ml/(kg·h),再灌注2h后下腔静脉取血,测定血清肌酐(Cr)。处死大鼠后摘除双眼球,左眼剥离视网膜,制作组织匀浆测定超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量;右眼做病理标本,观察其形态学改变,同时取距回盲部20cm一段小肠病理切片。结果:与C组相比,I组SOD活性显著降低(P<0.01),MDA含量则显著升高(P<0.01),血清Cr水平也显著升高(P<0.01)。光镜下病理结果显示:与C组相比,I组小肠黏膜上皮下间隙扩张,伴黏膜上皮层与固有层中度分离,且固有层中性粒细胞增多,部分绒毛顶端破损。视网膜内层明显水肿,神经节细胞分散,排列不规则;外核层分解、破坏。结论:大鼠小肠缺血再灌注可引起视网膜损伤,其机制可能与再灌注损伤引起过激的氧化反应,产生大量自由基有关。

Objective： To investigate the effects of intestinal ischemia-reperfusion （I/R） on retina in rats. Methods： Sixteen adult male Wistar rats were randomly divided into two groups （n =8 each）.Superior mesenteric artery （SMA） were separated from abdominal cavity and continuously injected 0.9% sodium chloride 10 ml/（kg, h） by pump in control group （C）.The ischemia group （I） was produced by clamping SMA for 60 min with a clip followed by 120 min reperfusion after removal of the clip and continuously injected 0.9% sodium chloride 10 ml/（kg, h）. Serum creatinine （Cr） from venous blood was determined at the end of 120 min reperfusion. Both eyeballs were taken out of rats which were sacrificed by decapitation at the end. The left one was immediately dissection for determination of tissue bomogenate superoxide dismutase （SOD） activity and malondialdehyed （MDA） content. The structural changes of the right one and the intestine were examined by microscopy with HE staining. Results： The SOD activity was significantly lower while MDA content and Cr level were higher in I group than those in C group （P〈0.01）.Under the microscope, compared with C group, intestinal subepithelial space dilated in I group,with epithelium mucosae segregating from lamina propria, in which neutrophilic granulocyte increased and part of villi top breakage. Meanwhile, entoretina edema obviously in retina, and ganglion ceils scattered with irregular because of the oppression of tissue fluid and outer nuclear layer decomposition. Conclusion： Intestinal ischemia-reperfusion in rats may cause retina injury which maybe related to excessive oxidizing reaction.