Nrf2-ARE Signaling Pathway Mediates Resveratrol Inhibiting Oxidative Stress In Rats With Cerebral Hemorrhage

Objective:In this study,We observe the effects of resveratrol(Res)on neurobehavioral score,brain tissue pathological staining,degree of brain edema,oxidative stress,cell apoptosis and the expression of Nrf2-ARE signaling pathway in rats with ICH,to investigate the possible mechanism of resveratrol for neuroprotection of ICH.Methods:120 male SD rats were randomly divided into three groups(n=40): sham group,ICH group and Resveratrol group(Res group),then each group was divided into 1d,3d,7d and 14 d subgroup,and 10 rats in each subgroup.The model of ICH was established by injecting autologous blood(50uL)into the right striatum of rats(coordinates: anterior fontanelle 0.2 mm,right side 3 mm,depth 6mm).After anesthesia recovery,the rats in Res group received daily intraperitoneally injection with the concentration of 50mg/kg.Sham group received the equal volumn of normal saline,and ICH group received equal volumn of 2% DMSO solution as reference.The neurological deficits were evaluated by Modified Neurological Severity Score(mNSS),the pathological changes and neuronal apoptosis were observed by HE/TUNEL staining,brain water content in rats were measured to evaluate cerebral edema.The oxidative stress parameters(MDA,GSH,SOD)were detected by ELISA,Nrf2 protein and HO-1 protein expression level were detected by western-blot.Results:1.mNSS score:(1)There was no obvious neurological deficit in sham group.(2)The mNSS score both in ICH group and Res group were significantly higher than sham group at all time points(P<0.01).(3)The mNSS score of rats at 3 d post surgery was the highest both in ICH group and Res group(P<0.05).(4)The mNSS score of Res group was significantly lower than ICH group at each time point(P<0.01).2.Brain water content:(1)There was no significant change in water content of brain tissue in sham group(P>0.05).(2)The brain water content both in ICH group and Res group were significantly higher than sham group at all time points(P<0.05).(3)The brain water content of rats at 3d post surgery was the highest both in ICH group and Res group(P<0.05).(4)Except for 14 d,the brain water content of Res group was significantly lower than ICH group at each time point(P<0.01).3.HE staining:In sham group,the morphology of brain tissue was complete,the arrangement of neurons was regular,the cells were normal,no pyknosis and fragmentation,no cell edema and necrosis in the nucleus;But the pathological injury were serious in ICH after 1-3d,especially in 3d,with obvious edema around the foci,swelling,degeneration,necrosis and pyknosis of nerve cells,it can be seen that a large amount of red blood cells accumulate and the inflammatory cells infiltrate obviously.After 7-14 d,the pathological changes of brain tissue were gradually alleviated,and the HE staining in Res group was less than ICH group.4.TUNEL staining in rats at 3d post surgery:(1)TUNEL staining in the brain of sham group showed no significant apoptosis.(2)Compared with the sham group,there was a larger number of neuronal apoptotic cells and significantly higher apoptosis index in ICH group(P<0.01).(3)But in Res group,apoptotic cells decreased and apoptosis index decreased significantly(P<0.01).5.Measurement of oxidative parameters at 3d post surgery:(1)The content of GSH and the activity of SOD both in ICH group and Res group were lower than sham group(P<0.01).(2)The level of GSH and SOD in Res group was significantly higher than ICH group after resveratrol administration(P < 0.01).(3)MDA,a lipid oxidative metabolite,was significantly increased both in ICH group and Res group(P<0.01).(4)The content of MDA in Res group was significantly lower than ICH group after resveratrol administration(P < 0.01).6.Western-Blot analysis:(1)The expression of Nrf2 protein and HO-1 protein at 3d post surgery was lower in sham group,while it was increased in ICH group and Res group(P<0.01).(2)Compared with ICH group,the Nrf2 protein and HO-1protein in Res group was further increased,and the difference was statistically significant(P<0.01).Conclusion:1.Resveratrol can play a neuroprotective role in ICH rats by reducing the degree of brain edema and the pathological injury of brain tissue,and inhibiting neuronal apoptosis,improving the mNSS score post ICH.2.Resveratrol can significantly reduce oxidative stress in brain tissue,thus reducing secondary brain injury of ICH.3.The activation of Nrf2-ARE signaling pathway may contribute to alleviate oxidative stress,so as to play a neuroprotective role and improve secondary brain damage of ICH.