Mechanism Of Melatonin Improves Sepsis Induced Myocardial Dysfunction Through Ripk3/Mitochondrial Pathway

BackgroundSepsis induced myocardial dysfunction(SIMD)is a serious threat to our health However,Sepsis is mainly treated with symptomatic treatment and lack of specific treatmentand.Its pathogenesis is not completely clear either.Inflammatory response,oxidative stress,mitochondrial damage,and endoplasmic reticulum stress cause dysfunction of myocardial cell energy metabolism and myocardial deathare the leading cause of death in patients with SIMD.Receptor-interacting protein kinase 3(Ripk3)activation is closely related to inflammatory progression and apoptosis.Inhibition of Ripk3 expression can reduce cell death by improving mitochondrial function and regulating endoplasmic reticulum stress.Ripk3 may be a common upstream signal for mitochondrial damage and endoplasmic reticulum stress.Melatonin is one of the most potent antioxidants in the body and has been extensively studied in the treatment of sepsis.It can treat sepsis through the PI3K/Akt pathway,inhibit NLRP3 inflammatory bodies,and have strong antioxidant properties.It was recently discovered that melatonin prevents Ripk3 activation and improves myocardial cell function during ischemia-reperfusion.In the case of septic myocardial injury,the relationship between melatonin,Ripk3 and SIMD is not clear.We found that after LPS-induced cardiomyocytes,Ripk3 was significantly reduced and myocardial survival time was prolonged.However,previous studies only confirmed the effectiveness of melatonin on sepsis SIMD at the cellular level,and did not confirm the inhibition of Ripk3 on the animal level.Improving the role and mechanism of SIMD in sepsis;therefore,we conducted cell and animal studies to investigate the effects of melatonin on cardiac function in sepsis Ripk3-/-mice;melatonin and Ripk3-/-mice Effects on myocardial cells in sepsis;whether melatonin improves myocardial cell mitochondrial function and endoplasmic reticulum stress through the Ripk3/mitochondrial pathway,thereby counteracting the damage to myocardium by sepsis and providing new targets for SIMD treatment.MethodsAt the animal level,a mouse SIMD model was constructed by intraperitoneal injection of lipopolysaccharide.Melatonin,Ripk3 knockout and overexpression intervention models were used.Immunofluorescence,Elisa,RT-PCR,Echocardiography and other methods to detect the effects of melatonin on myocardial cells and cardiac contractile function in sepsis Ripk3-/-mice;At the cellular level,SIMD cardiomyocytes were constructed.melatonin,Ripk3 knockout and overexpression intervention models were used to detect ATP content,MTT cell activity,immunofluorescence,Elisa method,LDH,TUNEL,Western Blot and other methods to detect fading.Effect of melanin on cardiomyocytes and cardiac contractile function in sepsis Ripk3-/-mice.We explore melatonin on mitochondrial energy metabolism,mitochondrial autophagy,fusion and division,endoplasmic reticulum stress,effects of apoptosis in Ripk3-/-miceResμltsIn animal experiments:Melatonin reduces serum inflammatory factors TNF-α,IL-10,and myocardial markers CK-MB,cTn-T levels in sepsis mice through Ripk3;Melatonin reduces Grl expression in myocardial tissue of sepsis mice through Ripk3;Melatonin improves cardiac contractility in sepsis mice through Ripk3;In cell experiments:Melatonin increases ATP,SOD,GPx levels,and MTT cell activity in LPS-induced sepsis myocardial cells through Ripk3;Melatonin reduces LPS levels in TUNEL-positive cells and cardiomyocytes in sepsis-induced myocardial tissues through Ripk3;Melatonin reduces the cellular expression of TUNEL and caspase-3 in LPS-induced sepsis cardiomyocytes through Ripk3;Melatonin increases mitochondrial length,mitochondrial fusion,and autophagy in sepsis-induced cardiomyocytes through Ripk3;Melatonin reduces mitochondrial division in sepsis-induced myocardial cells through Ripk3;Melatonin improves LPS-induced endoplasmic reticulum stress in sepsis myocardial cells through Ripk3.ConclusionOur research confirmed that melatonin reduces the oxidative stress and inflammation induced by LPS through the Ripk3 signaling pathway;restores mitochondrial autophagy,division,and fusion functions and reduces cardiomyocyte apoptosis.Melatonin improves myocardial contractile dysfunction in sepsis;protects myocardium from sepsis damage and maintains myocardial function,providing a new target for SIMD treatment.