The Role Of Mitochondrial Autophagy-NLRP3 Inflammasome Pathway In Cerebral Ischemia-reperfusion Injury And The Intervention Of Panax Notoginseng Saponins And Astragaloside IV

Previous studies have shown that NLRP3 inflammasome mediated cerebral ischemia reperfusion injury,and its activation can aggravate cerebral ischemiareperfusion injury.cerebral ischemia-reperfusion activated mitophagy,and mitophagy is an important potential target for cerebral ischemia-reperfusion intervention.Mitophagy is an important factor that inactivated the NLRP3 inflammasome in many diseases.Therefore,this study explores the regulation of NLRP3 inflammasome activation by mitophagy on cerebral ischemia reperfusion,and reveals the role of the mitophagy-NLRP3 inflammasome pathway in the pathological process of cerebral ischemia-reperfusion.Based on the multi-target protective mechanism of PNS(PNS)and astragaloside ?(AST-?)in cerebral ischemia reperfusion,and the role of mitophagy and NLRP3 inflammasome in cerebral ischemia-reperfusion,and the regulation of NLRP3 inflammasome activation by mitophagy.This study further explores the anti-cerebral ischemia-reperfusion mechanism of PNS and AST-? from the mitophagy-NLRP3 inflammasome pathwayPart 1This part aims to explore the regulation of NLRP3 inflammasome activation by mitophagy on cerebral ischemia reperfusion and to reveal the role of mitophagy-NLRP3 inflammasome pathway in cerebral ischemia reperfusion.After prepared cerebral ischemia and reperfusion model in rats by modified suture method.We found that NLRP3 inflammasome was activated in cerebral ischemia reperfusion,and inhibiting NLRP3 inflammasome or its downstream Caspase-1 could alleviate cerebral ischemia reperfusion injury in rats.It indicated that there was activation of NLRP3 inflammasome and the activation aggravated the cerebral ischemia reperfusion injury.Rapamycin,an autophagic agonist,can inhibit the activation of NLRP3 inflammasome during cerebral ischemia reperfusion in rats.It can also promote mitophagy through PINK1/Parkin pathway.Mitophagy mediates the inhibitory effect of rapamycin on the activation of NLRP3 inflammasome during cerebral ischemia-reperfusion and the anticerebral ischemia reperfusion injury effects in rats.But 3-MA,the autophagy inhibitor,had no effect on activation of NLRP3 inflammasome,which indicated that mitophagy could negatively regulate the activation of NLRP3 inflammasome in cerebral ischemia reperfusion to alleviate cerebral hypoperfusion injury.The mitophagy-NLRP3 inflammasome pathway played a protective role in cerebral ischemia reperfusion.Part 2This part aims to explore the anti-cerebral ischemia-reperfusion injury mechanism of PNS based on the mitophagy-NLRP3 inflammasome pathway.By the establishment of cerebral ischemia reperfusion model of middle cerebral artery embolism in rats,the intervention of PNS can reduce cerebral infarction volume and neurological function in rats,it indicated PNS alleviate cerebral ischemia reperfusion injury in rats.PNS can inhibit the activation of NLRP3 inflammasome and selectively promote mitophagy in cerebral ischemia-reperfusion.The inhibition of mitophagy can block the inhibitory effect of PNS on NLRP3 inflammasome,indicating that mitophagy mediates the inhibitory effect of PNS on the activation of NLRP3 inflammasome in cerebral ischemia-reperfusion.In addition,the levels of PINK1 and Parkin protein in mitochondria increased during cerebral ischemia-reperfusion in rats,while the levels of PINK1 and Parkin protein in brain mitochondria were further increased by PNS,suggesting that PNS may promote mitophagy during cerebral ischemia reperfusion through PINK1/Parkin pathway.This study revealed that PNS selectively promote mitochondria autophagy through PINK1/Parkin pathway,which can inhibit the activation of NLRP3 inflammasome during cerebral ischemia reperfusion and alleviate cerebral ischemia reperfusion injury.Part 3The present study was aimed to investigate the protective effect and anti-inflammation mechanism of astragaloside ?(AST-?)on cerebral ischemia and reperfusion injury.Following the establishment of cerebral ischemia and reperfusion model in rats by modified suture method,neurological deficit scores and cerebral infarct volume were used to evaluate the pharmacological effect of AST-? against cerebral ischemiareperfusion injury.Western blot was used to detect the expression levels of NLRP3,proCaspase-1,Caspase-1,pro-IL-1?,IL-1?,pro-IL-18,IL-18,phosphorylated and total nuclear factor kappa B(NF-?B)/p65 protein in the brain tissue.The results showed that,compared with model group,the intervention of AST-? decreased the neurological deficit scores,reduced the cerebral infarct volume,decreased the levels of NLRP3,Caspase-1,pro-IL-1?,IL-1?,pro-IL-18 and IL-18,and inhibited the expression of phosphorylated NF-?B in brain tissue.The results suggest that AST-? has a protective effect against cerebral ischemia and reperfusion injury,and its mechanism is related to inhibiting the phosphorylation of NF-?B and NLRP3 inflammasome activation.