| Research background and purpose:The study was designed to explore the protective effects and its mechanisms of pretreatment with procyanidins(PC)on oxidative stress injury following Intestinal ischemia/Reperfusion(IR)in rats.Materials and Methods:Twenty-four Sprague-Dawley(SD)male rats were randomly divided into four experimental groups:Sham group(n=6),IR group(n=6),IR+PC100 group(n=6)and IR+PC200 group(n=6).IR+PC100 group and IR+PC200 group were given gastric lavage pretreatment with 100mg/kg and 200mg/kg procyanidins per day respectively,and the other two groups were given gastric lavage pretreatment with equivalent physiological saline per day.The rats in each experimental group were pretreated according to the above protocols for 5 days,and the weight changes of rats in all experimental groups were recorded every day.After pretreatment for 5 days,IR injury model for rats was established by clamping Superior Mesenteric Artery(SMA)for 1 hour and reperfusion for 4 hours among IR group,IR+PC100 group and IR+PC200 group.The Sham group underwent the same operation without clamping SMA.After 1 hour of ischemia and 4 hours of reperfusion,the recovery of intestinum tenue following IR injury in each group was recorded by photographing.The slow wave activity of smooth muscle myoelectricity in intestinum tenue was monitored in vivo,and the slow wave frequency and amplitude of smooth muscle myoelectricity in intestinum tenue were recorded.The contraction activity of smooth muscle in intestinum tenue was measured and the contraction frequency and amplitude of smooth muscle in intestinum tenue were recorded.The serum was centrifuged from the blood in abdominal aorta to determine the contents of Nitric Oxide(NO)and Malondialdehyde(MDA)by using the kits,and the activity level of Hydroxyl Radical(OH~-)and Superoxide Dismutase(SOD)in ileum tissue homogenate were also measured by the kits.The Chiu scoring of intestinal mucosal injury by Hematoxylin Eosin(HE)staining,the water ratio of ileum tissue by wet and dry weight method and the expression of inflammatory factor such as Tumor Necrosis Factor-α(TNF-α)and Interleukin-1β(IL-1β)by Immunohistochemistry(IHC)were performed.Result:The weight measurement showed that the weight of rats in each experimental group displayed a slight upward trend during corresponding preconditioning.The photographing performed that the recovery of intestinum tenue in IR+PC100 group and IR+PC200 group were better than those in IR group.The slow wave activity and contraction activity of ileum smooth muscle showed that the frequency and amplitude of ileum smooth muscle slow wave activity and contraction activity in IR+PC100 group and IR+PC200 group were significantly higher than those in IR group(P<0.01).The determination results of serum fingered out that the content of NO and MDA in IR+PC100group and IR+PC200 group were significantly lower than that in IR group(P<0.01).The measurement results of ileum tissue homogenate showed that the intestinal activity of OH~-in IR+PC100 group and IR+PC200 group were lower than these in IR group(P<0.05),while the intestinal activity of SOD in IR+PC100 group(P<0.05)and IR+PC200group(P<0.01)were higher than those in IR group.The HE staining of ileum tissue showed that the Chiu scoring of intestinal mucosal injury in IR+PC100 group and IR+PC200 group were lower than these in IR group(P<0.01).The determination results of water ratio in ileum tissue suggested that the water ratio of ileum tissue in IR+PC100group and IR+PC200 group were lower than those in IR group(P<0.05).The measurement results of IHC in ileum tissue showed that the expression of TNF-αand IL-1βin IR+PC100 group and IR+PC200 group were significantly lower than these in IR group(P<0.01).Conclusion:The procyanidins possessed good biological safety.The pretreatment with procyanidins can inhibit the production of nitrogen free radicals and their metabolites after IR injury in rats by reducing the expression of TNF-αand IL-1βin intestinal mucosa and the content of NO and MDA in serum.Also,it can restrain the production of oxygen free radicals and their metabolites following IR injury in rats by improving the activity level of SOD in intestinal mucosa while removing excessive OH~-in intestinal mucosa.Based on the above effects,preconditioning with procyanidins can inhibit the inflammatory reaction and lipid peroxidation damage after IR injury in rats,relieve the degree of intestinal edema,reduce the damage degree of intestinal mucosa and further promote the recovery of intestinal electrophysiological activity and systolicmotor function,which is able to realize the protective effect on oxidative stress injury following IR in rats. |
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