Effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic ischemia-reperfusion in rats

Abstract

Objective To evaluate the effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic ischemia-reperfusion(I/R)in rats. Methods Healthy male Wistar rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups(n=16 each)using a random number table: sham operation group(Sham group), hepatic I/R group(I/R group)and limb ischemic preconditioning group(LIP group). In LIP group, the lower limb blood flow was blocked for 10 min with an elastic rubber tourniquet at the right groin followed by 30-min reperfusion through releasing the tourniquet.Hepatic I/R injury was induced by occlusion of the portal vein, hepatic artery and common bile duct for 30 min followed by reperfusion in I/R and LIP groups.Eight rats in each group were selected at 6 h of reperfusion and samples from the cardiac apex were taken for determination of plasma concentrations of tumor necrosis factor-alpha(TNF-α)and interleukin-10(IL-10)by radioimmunoassay.Then the rats were sacrificed and the small intestine tissues and brain tissues were removed.Intestinal damage was assessed and scored according to Chiu.The activity of myeloperoxidase(MPO)in intestinal mucosa was detected by colorimetric method.The pathological changes of brain tissues were examined under a light microscope.The ultrastructure of brain tissues was observed under an electron microscope.Eight rats in each group were randomly selected at 6 h of reperfusion, and Evans blue(EB)2 mg/kg was injected through the caudal vein over 1 min.Then the rats were sacrificed, brain tissues were removed for measurement of EB content, and the brain water content was calculated. Results Compared with Sham group, Chiu′s score and MPO activity in intestinal tissues were significantly increased, the brain water content and EB content were increased, and the concentrations of TNF-α and IL-10 in plasma were increased in I/R group and LIP group(P 0.05), and the pathological changes of brain tissues were significantly attenuated in LIP group. Conclusion Limb ischemic preconditioning can attenuate intestinal injury and brain injury induced by hepatic I/R, and the mechanism may be related to inhibiting systemic inflammatory responses of rats. Key words: Ischemic preconditioning; Limbs; Reperfusion injury; Liver; Intestine; Brain injuries