通心络胶囊通过GRP78/XBP1/CHOP途径调控内质网应激减轻大鼠心肌缺血再灌注损伤的作用研究OA

Objective To investigate the mechanism of action of Tongxinluo Capsule(TXL)in alleviating myocardial ischemia-reperfusion injury(MI/RI)in rats by regulating endoplasmic reticulum stress(ERS)via the glucose-regulated protein 78(GRP78)/X-box binding protein 1(XBP1)/C/EBP homologous protein(CHOP)pathway.Methods Forty-eight male SD rats were randomly divided into six groups:Sham operation(Sham)group,MI/RI group,positive control group[MI/RI+Atorvastatin(ATV),7.2 mg/kg],ERS inhibitor group[MI/RI+4-phenylbutyric acid(4-PBA),500 mg/kg],TXL group(MI/RI+TXL,1 g/kg),and targeted GRP78 inhibitor group(MI/RI+TXL,1 g/kg+HA15,15 mg/kg).Rats in each group received continuous intragastric administration for 7 days before modeling,with modeling performed 1 hour after the last dose.The MI/RI model was established by left anterior descending coronary artery ligation(50 minutes of ischemia followed by 4 hours of reperfusion).After reperfusion,left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS)were measured using echocardiography.Serum myocardial enzyme profiles[aspartate aminotransferase(AST),lactate dehydrogenase(LDH),creatine kinase(CK),and creatine kinase myocardial band(CK-MB)]were tested using an automatic biochemical analyzer with corresponding kits.Serum inflammatory cytokines[interleukin(IL)-1β and IL-18]were measured by ELISA.Serum oxidative stress indicators[glutathione(GSH),malondialdehyde(MDA),and total superoxide dismutase(T-SOD)]were determined using colorimetric assays.Myocardial tissue pathological changes were observed by HE staining.Myocardial collagen deposition was tested by Masson staining,and the collagen volume fraction(CVF)was calculated.Endoplasmic reticulum ultrastructure was observed by transmission electron microscopy.Collagen types Ⅰ and Ⅲ expressions were determined by immunohistochemical staining.GRP78/XBP1/CHOP pathway protein expression was measured by Western blot.Results Compared with the Sham group,the MI/RI group showed decreased LVEF and LVFS(P＜0.01);increased serumAST,LDH,CK,CK-MB,IL-1β,IL-18,and MDA(P＜0.01);decreased T-SOD and GSH(P＜0.01);disordered myocardial fibers with extensive inflammatory cell infiltration;increased CVF and collagen Ⅰ/Ⅲ expressions(P＜0.01);dilated and swollen endoplasmic reticulum;increased protein expressions of GRP78 and CHOP(P＜0.01);and decreased protein expression of XBP1(P＜0.01).Compared with the MI/RI group,the MI/RI+ATV group,MI/RI+4-PBA group,and MI/RI+TXL group showed increased LVEF and LVFS(P＜0.01);decreased serum AST,LDH,CK,CK-MB,IL-1β,IL-18,and MDA(P＜0.01);increased T-SOD and GSH(P＜0.01);improved myocardial fiber arrangement disorder and inflammatory infiltration;decreased CVF and collagen Ⅰ/Ⅲ expressions(P＜0.01);alleviated endoplasmic reticulum ultrastructural damage;decreased protein expressions of GRP78 and CHOP(P＜0.01);and increased XBP1 protein expression(P＜0.01).Compared with the MI/RI+TXL group,the MI/RI+TXL+HA15 group showed increased LVEF and LVFS(P＜0.01);decreased serum AST,LDH,CK,CK-MB,IL-1β,IL-18,and MDA(P＜0.05);increased T-SOD and GSH(P＜0.05);decreased CVF and collagenⅠ/Ⅲexpressions(P＜0.05);decreased protein expressions of GRP78 and CHOP(P＜0.05);and increased XBP1 protein expression(P＜0.05).Conclusion TXL can alleviate MI/RI in rats by regulating ERS,and this effect may be related to the GRP78/XBP1/CHOP pathway.