剪切力在大鼠小肠缺血再灌注损伤中的作用

Role of shear stress in small intestinal injury following intestinal ischemia reperfusion in rats

目的:探讨血流剪切力在小肠缺血再灌注(I/R)损伤中的作用及可能机制。方法:雄性Wistar大鼠90只,随机分为假手术组(Sham)、缺血再灌注模型组(I/R组)和缺血再灌注+利多卡因组(I/R+Lid组)。I/R组通过夹闭肠系膜上动脉根部30 min后再灌注,制做小肠I/R模型;I/R+Lid组再灌注前10 min给予利多卡因。Sham组同样完成手术,但不夹闭相应血管。各组于再灌注2、6、12和24 h分别检测小肠黏膜血流量,处死取材。观察病理学改变、Western Blot检测小肠黏膜损伤及微血管内皮相关蛋白的表达、ELISA检测小肠组织促炎性因子水平。结果:与Sham组相比,I/R组小肠黏膜血流显著减少(P<0.01)、小肠含水率增加(P<0.05),小肠病理损伤严重、氧化应激(P<0.05)和促炎性因子水平(P<0.01)明显升高、凋亡相关蛋白表达明显增加(P<0.05),微血管内皮CD31、e NOS的表达及NO水平明显下降(均P<0.05)。与I/R组同时点比较,I/R+Lid组各项指标均明显改善(均P<0.05)。结论:剪切力降低可引起小肠损伤,可能通过氧化应激、炎症反应导致小肠黏膜微循环障碍、小肠微血管内皮细胞功能受损,进而加重小肠I/R损伤;利多卡因通过增加剪切力对小肠I/R损伤发挥保护作用。

Objective: To explore the effect of shear stress on small intestinal injury following intestinal ischemia-reperfusion(I/R) in rats and investigate the underlying mechanism. Methods:Ninety Wistar rats were divided into 3 groups, that is, sham-operation group, ischemia-reperfusion group, and I/R+ Lidocaine group. The rat model of intestinal ischemia-reperfusion injury was induced by clamping the superior mesenteric artery for 30 min and then followed by reperfusion. Sham group with no intervention after abdominal opening. I/R+ Lidocaine group with an injection of lidocaine 2 mg/kg via femoral vein 10 min before reperfusion and the same volume of saline was given to Sham and I/R group. Intestinal mucosal blood flow(IMBF) was measured at 2, 6, 12, and 24 h following reperfusion and 10 rats were harvested at each time point. HE staining, Western blot and ELISA were used to detect intestinal cell injury, the level of oxidative stress and proinflammatory factor to clarify the effect of shear stress in intestinal I/R injury. Results: Compared with the Sham group,IMBF was reduced and tissue water content was significantly elevated in I/R group. HE-staining showed severe injury in the I/R group. The level of SOD, CD31, p-Enos, NOS in I/R group was significantly decreased(both P<0.05), while the level of MDA and IL-1β, IL-6, TNF-αand caspase-3 expression in I/R group significantly increased(both P<0.05). All indicators examined at each predefined time point of I/R+ Lidocaine group were significantly improved compared with those of the I/R group. Conclusion: The decrease of shear stress can lead to microvascular endothelial injury and further aggravate intestinal I/R injury by inducing oxidative stress and inflammatory response. A Lidocaine protects the small intestine from I/R injury by increasing shear stress.