The Effect Of Resveratrol Proconditioning On Intestinal Ischemia-reperfusion Injury And Potential Mechanisms In Mice

In the visceral organs, the small intestine is a most sensitive organ to ischemic injury. Some studies show that intestinal ischemia-reperfusion (I/R) injury represents a significant clinical problem in numerous situations, such as severe trauma, extensive burns, shock, severe pancreatitis and so on. With the recent research, the gut has been implicated to serve as the triggers that initiate the SIRS and MODS experimentally and clinically. Intestinal ischemia-reperfusion injury can not only cause local damage of intestinal tissue, but also has been related to loss of gut barrier function and the ensuing translocation of bacteria and endotoxin from the gut to the portal and systemic circulations, leading to sepsis and shock, further damaging the liver, lungs, kidneys and other organs, and ultimately leading to death. Therefore, the focus of current research is to investigate the molecular mechanisms of intestinal ischemia-reperfusion injury and identify the potential treatment.Resveratrol(3,5,4'-trihydroxy-trans-stilbene) is a stilbenoid, a type of natural phenol. Resveratrol was originally isolated by Takaoka from the roots of hellebore in 1940, and later, in 1963, from the roots of Japanese knotweed. The presence of resveratrol in more than 70 plant species spanning 32 genera has been reported. In fresh grape skin, resveratrol concentration is the highest, containing about 50~100 mg of resveratrol per gram wet weight. However, it attracted wider attention only in 1992, when its presence in red wine was suggested as the explanation for cardioprotective effects of red wine, the phenomenon is termed the"French Paradox". Henceforth, growing studies suggest that resveratrol possesses a wide variety of beneficial effect across species and disease models, including phytoestrogens, anti-tumor, anti-inflammatory, protecting cardiovascular function, enhancing insulin sensitivity, free radical scavenging and anti-aging. Furthermore, in 1999, Ray et al first reported that resveratrol could ameliorate myocardial ischemia-reperfusion injury by decreasing oxidative stress.In this study, we determined the protective effect of resveratrol on oxidative stress during the intestinal I/R injury in mice. Meanwhile, it has been confirmed that nitric oxide was an important mediator during the process of intestinal I/R injury. So the effects of resveratrol on nitric oxide pathway were investigated to provide a mechanistic basis for the protective effect of resveratrol on intestinal I/R injury.ⅠThe protective role of resveratrol on the intestinal I/R injury and its effect on oxidative stress in miceObjective To discuss the influence of resveratrol on the intestinal I/R injury and its effect on oxidative stress in mice. Methods Adult male BALB/c mice were randomly assigned to one of following groups: (a) Sham group: All surgical steps were performed, except that intestinal I/R was not induced; (b) I/R group: Mice receiving corresponding volume of saline solution (0.9% NaCl) containing 1% dimethyl sulfoxide by gavaging were used as control; (c) Resveratrol group: Intestinal I/R was performed and resveratrol (50 mg/kg body wt/day) was fed by gavaging for 10 days. Intestinal injury was evaluated by intestinal morphology and myeloperoxidase (MPO) activity. Tissue antioxidant enzymes and oxidant products were determined. Results In the I/R mice intestines, we decected severe tissue injuries, the significant increase in the tissue levels of MDA and MPO activities, and the decrease in SOD activities and GSH levels, compared to the sham group. Resveratrol significantly ameliorated the intestinal injury, decreased MDA levels and MPO activities, and restored the SOD activities and GSH levels. Conclusion These data suggest that resveratrol could protect intestinal tissue against I/R injury with its potent antioxidant properties.ⅡResveratrol attenuates intestinal ischemia-reperfusion injury through NO pathwayObjective It has been confirmed that nitric oxide (NO) was an important mediator during the process of intestinal I/R injury. NO can modulate intestinal integrity by inhibiting neutrophil activation and scavenging ROS. So the effects of resveratrol on NO pathway were investigated to provide a mechanistic basis for the protective effect of resveratrol on intestinal I/R injury. Methods Adult male BALB/c mice were were randomly divided into three groups as described: (a) Sham group: All the surgical steps were performed, except that intestinal I/R was not induced. Animals were kept under anesthesia for the duration of the intestinal I/R method; (b) I/R group: Mice receiving corresponding volume of saline solution (0.9% NaCl) containing 1% dimethyl sulfoxide by gavaging were used as control. Intestinal I/R was performed and served as control of resveratrol group; (c) Resveratrol group: Intestinal I/R was performed and resveratrol (50 mg/kg body wt/day) was fed by gavaging for 10 days before the experiment. NO levels and total NOS activity was observed. The expression of iNOS, eNOS and SIRT1 were investigated with RT-PCR and western blot. NF-κB activity was analyzed by indirect immunofluorescence assay using confocal microscopy. In addition, the effect of resveratrol on IκBαphosphorylation was observed. Results After ischemia reperfusion, a slight decrease in NO levels and total NOS activity was observed in I/R group compared with sham group. In contrast, resveratrol preconditioning induced a remarkable increase in nitric oxide levels and total NOS activity compared with I/R group. An increased induction of eNOS was found in resveratrol group as compared to I/R group, while iNOS down-regulation became apparent. After intestinal I/R injury, the intracellular p65 translocated from the cytoplasm to the nucleus. This translocation was greatly inhibited by resveratrol preconditioning. In addition, IκBαphosphorylation increased in I/R group, and this phosphorylation was inhibited by resveratrol. Furthermore, we observed that resveratrol preconditioning significantly increased SIRT1 mRNA and protein expression. Conclusions Our study indicated that resveratrol might attenuate intestinal I/R injury through NO pathway. This finding might provide a basis for the development of novel therapeutic strategies for protection against the damages caused by intestinal I/R injury.