瘦素通过FAK/Src途径对心肌梗死大鼠心功能及心室重构的作用研究

Study on the effect of leptin on cardiac function and ventricular remodeling in rats with myocardial infarction through FAK/Src pathway

目的 探究瘦素对急性心肌梗死(AMI)大鼠的作用及其可能的作用机制。方法 将32只SD大鼠随机分为Sham组、AMI组、AMI+瘦素组、AMI+瘦素+Y15组,每组8只。通过丝线结扎左冠状动脉前降支建立AMI模型,AMI+瘦素组大鼠腹腔注射瘦素10μg/mg, AMI+瘦素+Y15组大鼠腹腔注射瘦素10μg/mg和FAK抑制剂Y15 30 mg/kg,每天1次,连续给药14 d。超声诊断仪检测大鼠心功能;ELISA试剂盒检测血清CK-MB、LDH、IL-6、TNF-α和IL-1β水平;Western blot检测瘦素、Ⅰ型胶原、α-平滑肌肌动蛋白(SMA)、p-FAK、FAK、p-Src和Src蛋白表达;HE染色检测心肌病理学变化;Masson染色检测心肌纤维化;免疫组化检测α-SMA表达。结果 Sham组大鼠心肌结构无明显异常;AMI组大鼠心肌细胞排列紊乱,有明显炎性细胞浸润,左心室收缩末期内径(LVESD)、左心室舒张末期内径(LVEDD)、胶原纤维面积、α-SMA阳性面积、瘦素、Ⅰ型胶原、α-SMA、p-FAK/FAK和p-Src/Src蛋白表达水平以及CK-MB、LDH、IL-6、TNF-α和IL-1β水平显著高于Sham组(P<0.05),左心室射血分数(LVEF)和左心室缩短分数(FS)显著低于Sham组(P<0.05);AMI+瘦素组大鼠心肌病理学变化较AMI组进一步加深,LVESD、LVEDD、胶原纤维面积、α-SMA阳性面积、瘦素、Ⅰ型胶原、α-SMA、p-FAK/FAK和p-Src/Src蛋白表达水平以及CK-MB、LDH、IL-6、TNF-α和IL-1β水平显著高于AMI组(P<0.05),LVEF和FS显著低于AMI组(P<0.05),FAK抑制剂Y15能部分逆转瘦素对AMI大鼠的作用。结论 瘦素可能通过激活FAK/Src途径促进AMI大鼠心功能障碍及心室重构。

Objective To explore the effect of leptin on acute myocardial infarction(AMI)in rats and its possible mechanism.Methods A total of 32 SD rats were randomly divided into Sham group,AMI group,AMI+leptin group and AMI+leptin+Y15 group,with 8 rats in each group.The AMI model was established by ligating the left anterior descending coronary artery with silk thread.The rats in the AMI+leptin group were intraperitoneally injected with leptin 10μg/mg,and the rats in the AMI+leptin+Y15 group were intraperitoneally injected with leptin 10μg/mg and Y1530 mg/kg,once daily for 14 days.Ultrasound diagnostic instrument was used to detect rats′heart function;ELISA kit was used to detect the levels of CK-MB,LDH,IL-6,TNF-αand IL-1βin serum;Western blot was used to detect the expressions of leptin,type I collagen,α-SMA,p-FAK,FAK,p-Src and Src protein;HE staining was used to detect the myocardial pathological changes;Masson staining was used to detect the myocardial fibrosis;immunohistochemistry was used to detect the expression ofα-SMA.Results There was no obvious abnormality in the myocardial structure of the rats in the Sham group.The myocardial cells in AMI group were arranged disorderly,with obvious inflammatory cell infiltration;the LVESD,LVEDD,collagen fiber area,α-SMA positive area,the expression levels of leptin,type I collagen,α-SMA,p-FAK/FAK and p-Src/Src protein as well as the levels of CK-MB,LDH,IL-6,TNF-αand IL-1βin AMI group were higher than those in Sham group(P<0.05),and LVEF and FS were lower than those in Sham group(P<0.05).The pathological changes of myocardium in AMI+leptin group were greater than those in AMI group;the LVESD,LVEDD,collagen fiber area,α-SMA positive area,the expression levels of leptin,type I collagen,α-SMA,P-FAK/FAK and p-Src/Src protein as well as the levels of CK-MB,LDH,IL-6,TNF-αand IL-1βin AMI+leptin group were higher than those in AMI group(P<0.05),while LVEF and FS were lower than those in AMI group(P<0.05);FAK inhibitor Y15 could partially reverse the effect of leptin on AMI rats.Conclusion Leptin may promote the cardiac dysfunction and ventricular remodeling in AMI rats by activating the FAK/Src pathway.