The Expression And Role Of Sesn2 In Sepsis-induced Myocardial Injury In Rats

BACKGROUNDSepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection,characterized by systemic inflammatory response syndrome.Sepsis induced myocardial injury is a common and severe complication,which is closely related to the prognosis.It is believed that mitochondrial oxidative stress and mitochondrial dysfunction play a key role in the pathogenesis of sepsis induced myocardial injury.Sesn2,an important member of the Sestrins(Sesns)protein family,has a pleiotropic biological function.A recent study has found that Sesn2 may play a protective role in sepsis.However,the relationship between Sesn2 and sepsis induced myocardial injury is still unclear.Therefore,this study focused on Sesn2 expression in myocardial tissue during sepsis and its mechanisms.OBJECTIVETo explore the correlation between Sesn2 and sepsis induced myocardial injury,and to investigate the role and mechanism of Sesn2 in sepsis induced myocardial injury.METHODSPart ?:Experimental rats were divided into normal control group and sepsis group(12 h,24 h and 48 h).Heart tissue and serum samples were taken,and CK and lactate dehydrogenase LDH were detected by microplate reader.Flow cytometry was used to detect activity.The levels of ROS and MMP were detected by RT-PCR,Western blot and immunohistochemistry.The expression of Sesn2 mRNA and protein was detected by HE staining and electron microscopy.Part ?:Neonatal SD rat cardiomyocytes were isolated and cultured according to theliterature,and then stimulated with 25?g/ml LPS at 0h,6h,12h,and 24h,respectively.The expression of Sesn2 was detected.Subsequently,lentiviral virus were used to silence the expression of Sesn2 gene in cardiomyocytes,and cardiomyocytes were randomly divided into five groups,namely:virus-loaded group(siRNA-NC group),Sesn2 lentiviral interference group(siRNA-Sesn2 group),and no-load virus + LPS group.(siRNA-NC + LPS group)and Sesn2 lentiviral interference group + LPS group(siRNA-Sesn2 + LPS group).The expression of Sesn2 was determined by WB and RT-PCR in cardiomyocytes as required to ensure that the Sesn2 protein was effectively silenced.Myocardial damage indicators(LDH,TNF-?,and IL-1?)levels,oxidative stress indicators(ROS,MDA,and SOD)levels,mitochondrial function-related indicators(mtDNA,MMP,and ATP)levels,and mitochondrial biogenesis-related proteins(PGC-1??NRF-1 and TFAM)were detected,and the morphological changes of mitochondria in cardiomyocytes were observed by electron microscopy.RESULTSPart ?:1.Myocardial injury(increased CK,CK-MB and LDH levels),especially myocardial mitochondrial structure and function injury(increased ROS level and decreased MMP level)occurred in the sepsis group.2.Both Sesn2mRNA and protein expression levels were increased in the myocardial tissue of rats in the sepsis group.3.In the sepsis group,the expression of myocardial mitochondrial ROS was positively correlated with Sesn2,while MMP was negatively correlated with Sesn2.Part ?:1.Both Sesn2mRNA and protein expression in cardiomyocytes were increased by LPS stimulation.2.LPS can induce cardiomyocytes injury(elevated levels of LDH,TNF-? and IL-10),oxidative stress(elevated levels of ROS and MDA,decreased levels of SOD),mitochondrial structure and function injury(decreased levels of MMP,ATP and mtDNA),as well as the enhancement of mitochondria biogenesis(increased expression of PGC-1?,NRF-1 and TFAM mRNA),while Sesn2 knowdown inhibits mitochondria biogenesis,increase oxidative stress and mitochondrial dysfunction,which lead to more severe cardiomyocytes injury.Conclusion:1.Sesn2 expression is closely related to myocardial injury in sepsis,especially mitochondrial injury;2.Sesn2 has a protective effect on cardiomyocytes injury in sepsis,which may protect cardiomyocytes by enhancing mitochondrial biogenesis,alleviating oxidative stress and mitochondrial dysfunction.