Role And Mechanism Of Sestrin2 In Early Brain Injury After Subarachnoid Hemorrhage In Rats

BackgroundSestrin2(Sesn2)is an important member of the Sestrin family,which is a group of highly conserved proteins that are induced by environmental stresses,including DNA damage,oxidative stress,and hypoxia.It has been well established that Sesn2 is a powerful free radical scavenger.Study results indicate that sestrin2 plays a neuroprotective role in neurodegenerative diseases(MPTP Parkinson 's model).Researches also showed that sestrin2 has an antioxidant protective effect in the liver by enhancing the autophagic degradation of Keap1,reducing the oxidative damage of liver.But its role in early brain injury(EBI)after subarachnoid hemorrhage(SAH)is unreported.Objective:To discuss the role and mechanism of Sestrin2 in early brain injury after subarachnoid hemorrhage in rats.Methods(1)SAH model was performed by injecting autologous blood into the prechiasmatic cistern of the rat.(2)Sesn2-interfered rat SAH model was established.Sesn2 Si RNA was injected into ventricle 24 hours before SAH modeling.(3)The effect of Sesn2-interfered gene on the brain tissue injury(Nissl's staining)around the hematoma during the early brain injury of rat SAH model was observed.(4)The effect of Sesn2-interfered gene on oxidative stress injury during early brain injury of rate SAH model was observed.By detecting the activity of SOD and content of MDA in cerebral homogenate,the effect of Sesn2-interfered gene on early brain injury of rat SAH model was assessed.(5)The effect of Sesn2-interfered gene on the Keap1/Nrf2 pathway(Real-time q PCR)and the expression of downstream antioxidant enzymes HO-1 and NQO1(Real-time q PCR and Western blot)was observed in the early brain injury of rat SAH model.Results(1)Compared with that of the SAH group,after Sesn2 was interfered,neurons in the brain tissue of the hemorrhage was decreased in terms of number and atrophied,and Nissl bodies disappeared.(2)Compared with that in Sham group,the level of MDA in SAH group was significantly increased,while the level of SOD was significantly decreased.Compared with that in SAH group,after Sesn2 was interfered,the level of MDA was further increased,while the level of SOD was further decreased,nerve cell injury was significantly increased,and oxidative stress was significantly enhanced.(3)Compared with that of the Sham group,the expression of Sesn2,Nrf2,HO-1 and NQO1 in SAH group was significantly increased,the expression of Keap1 was decreased,after Sesn2 was interfered,Compared with that in SAH group,the expression of Sesn2 and Nrf2 and HO-1 and NQO1 in antioxidant enzyme were significantly decreased,while the expression of Keap1 was significantly increased;Conclusions(1)Interference on Sesn2 can increase the level of brain injury and oxidative stress after SAH,which suggests that Sesn2 has a neuroprotective effect.(2)Keap1/Nrf2 pathway can be activated after SAH,the expression product at downstream of this pathway can be activated,which achieves neuroprotective effect.After the Sesn2 is silenced,the mechanism of aggravated brain oxidative stress injury may inhibit the Keap1/Nrf2 pathway by reducing the degradation of Keap1 and thereafter reduce the synthesis of a series of antioxidant enzymes and detoxification enzymes and enhance oxidative stress.