The Role And Mechanism Of CHI3L1 In Inhibiting Myocardial Cell Apoptosis And Promoting Angiogenesis In Rats With Myocardial Infarction By Aerobic Exercise

Objectives:Appropriate exercise has a protective effect on the heart of the heart,but the specific mechanism of exercise to protect the heart of the heart has not been fully elucidated.Chitinase-3-like protein 1(CHI3L1)is a secreted glycoprotein distributed in the liver,heart,brain,kidney,muscle,fat,etc.,which plays a role in inflammation and tissue remodeling.It has a cell growth factor-like effect and activates the PI3K-AKT/ERK signaling pathway,promotes cell mitosis and growth,and inhibits apoptosis.Exercise can promote the expression of Chitinase-3-like protein 1(CHI3L1)in vivo,but whether CHI3L1 plays a role in aerobic exercise inhibiting cardiomyocyte apoptosis and promoting angiogenesis in myocardial infarction rats,The specific molecular mechanism has not been reported in the literature.In this paper,whether CHI3L1 has a protective effect on heart infarction is the entry point,and the role of CHI3L1 in cardiomyocyte apoptosis and myocardial angiogenesis in rats with myocardial infarction is studied.Methods:Animal experiment:SD rats were randomly divided into normal group(C)and normal exercise group(CE).SD rats were prepared by left anterior descending coronary artery ligation(LAD)and randomly divided into sham operation group(S)and myocardial infarction group(MI),myocardial infarction aerobic exercise group(ME),8 in each group,and injection of PAR-2 blocker(FSLLRY-amide,150mg/kg),divided into 7 days after myocardial infarction PAR2 blocker group(7d+FS),7 days after myocardial infarction saline group(7d+SA),myocardial infarction After 14 days,PAR2 blocker group(14d+FS),myocardial infarction group 14d after saline group(14d+SA),every group have 8 rats.After 1wk after surgery,the ME group performed 4wk aerobic exercise after 1wk adaptive treadmill exercise.Abdominal anesthesia was performed the next day after the end of training,and hemodynamic parameters were evaluated for cardiac function;H9C2 cell experiment:Using rhCHI3L1(150 ng/ml,24h),AMPK agonist(AICAR,50 mM,24 h),PAR2 receptor blocker(Veliparib,10 1 h),PI3K inhibitor(LY294002,10?g/ml,40 min),lipopolysaccharide(LPS,10?g/ml,4h)intervention in H9C2 cells,H9C2 cells were divided into H9C2 group,+rhCHI3L1 group,+AICAR group,+AICAR+rhCHI3L1 group,+rhCHI3L1+Veliparib,+AICAR+Veliparib,+CHI3L1+AICAR+Veliparib,LPS group,+rhCHI3L1+LPS group,+AICAR+LPS group,+rhCHI3L1+AICAR+LPS group,+LY294002+LPS group,+LY294002+rhCHI3L1+LPS group,a total of 13 groups,used to study the proliferation and apoptosis mechanism at the cellular level.HUVEC cell experiment:Cultured human umbilical vein endothelial cells(HUVEC),rhCHI3L1(120 ng/ml,24 h),AMPK agonist(AICAR,2 mM,24 h),PAR2 receptor blocker(Veliparib,10 ?M,1 h),PI3K inhibitor(LY294002,10 ?g/ml,30 min)interfered with HUVEC cells.HUVEC cells were divided into HUVEC group,+rhCHI3L1 group,+AICAR group,+rhCHI3LI+AICAR group,+LY294002 group,+LY294002+rhCHI3L1 group,+Veliparib+AICAR group,+LY294002+AICAR,+LY294002+Veliparib+AICAR group Total of 9 groups for studying the mechanism of angiogenesis.Detection index:Masson staining The myocardial collagen volume percentage(CFV%)was observed;Immunofluorescence was used to observe the proliferation of H9C2 and heart tissue sections,and Tunel was used to detect H9C2 and heart tissue cell apoptosis.CCK-8 was used to detect cell viability;cell scratch and tubule formation were used to detect HUVEC cell migration and differentiation and tubule formation ability;Western blotting was used to detect the expression of CHI3L1,PAR2,pPI3K/PI3K,pAKT/AKT,pERK/ERK,Cyclin D1,Bax/Bcl-2 and eNOS protein in H9C2;HUVE and myocardium;CHI3L1 content in rat serum was detected by ELISA kit.Results:(1)Aerobic exercise significantly increased serum CHI3L1 levels and increased cardiac CHI3L1 protein expression in normal rats;significantly increased CHI3L1 and its receptor PAR2 protein expression in MI.(2)Aerobic exercise significantly increased myocardial pPI3K/PI3K,pAKT/AKT,pERK/ERK ratio and eNOS expression and Cyclin D1,decreased TUNEL particle number and Bax/Bcl-2 ratio,increased MI myocardial tissue PCNA+/vWF+ and The number of KI67+/cTnT+.It is indicated that aerobic exercise significantly activates PI3K-AKT/ERK-eNOS,PI3K-AKT/ERK-Cyclin D1 and PI3K-AKT/ERK-Bax/Bcl-2 signaling pathways,inhibiting apoptosis and promoting angiogenesis.(3)Aerobic exercise significantly reduced myocardial collagen volume percentage(CVF%)and left ventricular LVEDP,significantly increased left ventricular ±dp/dt max and LVSP.It is shown that aerobic exercise significantly reduces MI myocardial fibrosis and improves cardiac function.(4)CHI3L1 receptor PAR2 blocker(FSLLRY-amide)significantly decreased the ratio of pPI3K/PI3K,pAKT/AKT and pERK/ERK at MI 7d;significantly inhibited myocardial PI3K-AKT/ERK signaling pathway.Significant inhibition of myocardial PI3K-AKT/ERK signaling pathway at MI 14d increased MI myocardial collagen volume percentage and left ventricular LVEDP,significantly reducing left ventricular±dp/dt max and LVSP.The results showed that the myocardial collagen area increased significantly after 14 days of continuous injection of CHI3L1 receptor PAR2 blocker,and the cardiac function of myocardial infarction decreased.(5)AICAR intervention up-regulated CHI3L1/PAR2 protein expression in H9C2 cells.It is suggested that exercise significantly up-regulates CHI3L1 and its receptor PAR2 expression in H9C2 cells.(6)Exogenous rhCHI3Ll or(and)AICAR intervention significantly increased KI67+/cTnT+and CCK8 values in H9C2 cardiomyocytes.It was shown that exogenous rhCHI3L1 or(and)AMPK agonist AICAR intervention significantly increased H9C2 cell proliferation.(7)Exogenous rhCHI3L or(and)AICAR intervention significantly increased the ratio of pPI3K/PI3K,pAKT/AKT and pERK/ERK.It was shown that exogenous rhCHI3L1 or(and)AICAR intervention significantly activated the PI3K-AKT/ERK signaling pathway.(8)CHI3L1 receptor PAR2 inhibitor(Veliparib)significantly reduced the ratio of pPI3K/PI3K,pAKT/AKT and pERK/ERK in H9C2 cells.It is shown that CHI3L1 or(and)exercise intervention works through the PI3K-AKT/ERK/signal pathway.(9)CHI3L1 receptor PAR2 inhibitor(Veliparib)significantly increased the number of TUNEL positive particles,significantly reducing the ratio of Bax/Bcl-2 after rhCHI3L1 or(and)AICAR intervention.It was shown that rhCHI3L1 or(and)AICAR intervention significantly inhibited LPS-induced apoptosis of H9C2 cells.(10)Exogenous rhCHI3L1 or(and)AICAR intervention significantly improved LPS inhibition of PI3K-AKT/ERK signaling pathway in H9C2 cells and played a role in inhibiting cardiomyocyte apoptosis.(11)PI3K inhibitor(LY294002)significantly inhibited CHI3L1 phosphorylation of PI3K-AKT/ERK and increased Bax/Bcl2 ratio;rhCHI3L1 intervention significantly increased pPI3K/PI3K,pAKT/AKT and pERK/ERK and significantly decreased Bax/Bcl2 The ratio.It was shown that CHI3L1 inhibits apoptosis of H9C2 cells by activating the PI3K-AKT/ERK pathway.(12)AICAR intervention in HUVEC cells significantly up-regulated the expression of CHI3L1 and its PAR2 receptor,indicating that exercise significantly up-regulated the protein expression of CHI3L1 and its receptor PAR2 in HUVEC.(13)The AICAR intervention group significantly increased the phosphorylation level and eNOS expression of PI3K,AKT and ERK in HUVEC cells;LY294002 and AICAR intervention significantly decreased PI3K,AKT and ERK phosphorylation levels and eNOS expression.It is shown that exercise significantly activates the PI3K-AKT/ERK-eNOS signaling pathway and promotes angiogenesis.(14)rhCHI3L1 or(and)AICAR intervention significantly increased eNOS protein expression and migration and differentiation ability in HUVEC cells;rhCHI3L1 or(and)AICAR intervention for 12h significantly promoted HUVEC tubule formation.It was shown that rhCHI3L1 or(and)exercise intervention significantly up-regulated eNOS expression and promoted HUVEC tubule formation.(15)rhCHI3L1 intervention significantly up-regulated PI3K,AKT,ERK phosphorylation and eNOS expression in HUVEC cells.PI3K inhibitor LY294002 significantly decreased PI3K,AKT,ERK phosphorylation and eNOS expression,indicating that rhCHI3L1 significantly activated PI3K-AKT/ERK signal The pathway promotes angiogenesis.conclusion:(1)Aerobic exercise significantly increased the expression level of CHI3L1/PAR2,promoted mitosis of MI cardiomyocytes,inhibited myocardial cell apoptosis,decreased MI myocardial fibrosis,and improved MI cardiac function.(2)CHI3L1/PAR2-PI3K-AKT/ERK-Bax/Bcl2 signaling pathway was significantly activated by exercise,inhibiting H9C2 cardiomyocyte apoptosis.(3)Exercise significantly activated the expression of CHI3L1/PAR2-PI3K-AKT/ERK-eNOS in HUVEC cells and induced the formation of tubules in HUVEC cells.Therefore,CHI3L1 plays an important role in aerobic exercise to improve MI cardiac function.The mechanism is to inhibit the expression of Bax/Bcl2 and decrease the apoptosis of myocardial cells through CHI3L1/PAR2-PI3K-AKT/ERK signaling pathway;up-regulate the expression of eNOS Level,promote myocardial angiogenesis in MI,improve microcirculatory disorders,reduce MI myocardial fibrosis,and improve cardiac function.