腺苷A2a受体激动剂(CGS21680)对体外循环大鼠心肌功能的影响及其作用机制

Effects of adenosine A2a receptor agonist(CGS21680)on myocardial function in rats undergoing cardiopulmonary bypass and its mechanism

目的探讨腺苷A2a受体激动剂(CGS21680)对体外循环(CPB)大鼠心肌功能的影响及其作用机制。方法 45只SD大鼠按照随机数字表法分为对照组、模型组和治疗组。模型组和治疗组进行体外循环2 h。治疗组体外循环后经尾静脉注射腺苷A2a受体激动剂CGS21680 35 mg/kg,对照组和模型组尾静脉注射等体积生理盐水。两组治疗3 d后,测定各组大鼠乳酸脱氢酶(LDH)和肌酸激酶同工酶(CK-MB)表达水平;采用试剂盒检测各组血清丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽氧化物酶(GSH-px)水平;末端脱氧核苷酸转移酶介导的dUTP缺口末端标记(TUNEL)染色分析各组大鼠心肌细胞凋亡;采用蛋白质免疫印迹分析内质网应激相关蛋白表达水平。评价3组大鼠神经功能缺失评分;采用试剂盒检测氧化应激指标变化;采用TUNEL染色分析3组大鼠脑组织神经元凋亡比例;采用Western blot分析3组大鼠内质网应激(ERS)标志物葡萄糖调节蛋白78(GRP78)、C/EBP同源蛋白(CHOP)和半胱氨酸天冬氨酸蛋白酶-12(Caspase-12)表达水平。组间计量资料比较采用t检验。结果治疗组大鼠外周血LDH和CK-MB水平[(410.58±25.22)、(9.44±2.71) mmol/L]明显低于模型组[(812.39±30.91)、(16.23±3.93) mmol/L],差异有统计学意义(t=3.518、4.271,P<0.05)。治疗组大鼠外周血MDA水平[(8.31±1.79) mmol/L]明显低于模型组[(13.48±2.11) mmol/L],差异有统计学意义(t=3.984,P<0.05)。治疗组大鼠外周血SOD活性[(172.12±19.37) U/mg]明显高于模型组[(120.32±15.33) U/mg],差异有统计学意义(t=3.109,P<0.05)。治疗组大鼠外周血肿瘤坏死因子-α(TNF-α)和白细胞介素-1β(IL-1β)水平[(106.81±12.89)、(71.56±7.36) pg/g]明显低于模型组[(186.38±18.93)、(109.49±11.43) pg/g],差异有统计学意义(t=6.008、5.381,P<0.05)。治疗组大鼠心肌细胞凋亡率[(9.32±2.36)%]明显低于模型组[(18.54±4.18)%],差异有统计学意义(t=4.827,P<0.05)。治疗组大鼠心肌细胞GRP78、CHOP和Caspase-12表达水平(0.71±0.11、0.78±0.13、0.62±0.10)明显低于模型组(1.03±0.13、1.24±0.12、0.91±0.10),差异有统计学意义(t=2.891、3.012、2.895,P<0.05)。结论腺苷A2a受体激动剂(CGS21680)可显著改善机体氧化应激反应和炎性因子水平,降低心肌细胞内质网应激,降低心肌细胞凋亡,进而保护心肌细胞功能。

Objective To investigate the effect of adenosine A2A receptor agonist(CGS21680)on myocardial function in rats with cardiopulmonary bypass(CPB)and its mechanism.Methods Forty-five SD rats were randomly divided into control group,model group and treatment group.Rats in the model group and treatment group were given cardiopulmonary bypass for 2 hours.After cardiopulmonary bypass,CGS2168035 mg/kg adenosine A2a receptor agonist was injected via caudal vein in the treatment group,and equal volume of normal saline was injected via caudal vein in the control group and model group.After 3 days of treatment,the expression levels of lactate dehydrogenase(LDH)and creatine kinase isoenzyme(CK-MB)were measured.The serum levels of malondialdehyde(MDA)and superoxide dismutase(SOD)were detected by kit.The cardiomyocyte apoptosis was analyzed by terminal deoxynucl neotidyl transferase mediated dUTP nick end labelling(TUNEL)staining.T test was used to compare the measurement data between three groups.Results The levels of LDH and CK-MB in peripheral blood of rats in the treatment group[(410.58±25.22),(9.44±2.71)mmol/L]was significantly lower than that in the model group[(812.39±30.91),(16.23±3.93)mmol/L,t=3.518,4.271,P<0.05].The MDA level in the treatment group[(8.31±1.79)mmol/L]was significantly lower than that in the model group[(13.48±2.11)mmol/L,t=3.984,P<0.05].The SOD activity in the treatment group[(172.12±19.37)U/mg]was significantly higher than that in the model group[(120.32±15.33)U/mg,t=3.109,P<0.05].tumor necrosis factor-α(TNF-α)and interleukin-1(IL-1)in peripheral blood of rats in treatment groupβLevel[(106.81±12.89),(71.56±7.36)pg/g]was significantly lower than that in model group[(186.38±18.93),(109.49±11.43)pg/g,t=6.008,5.381,P<0.05].The apoptosis rate of cardiomyocytes in the treatment group[(9.32±2.36)%]was significantly lower than that in the model group[(18.54±4.18)%,t=4.827,P<0.05].The expression levels of GRP78,CHOP and Caspase-12 in cardiomyocytes of treatment group(0.71±0.11,0.78±0.13,0.62±0.10)was significantly lower than that in the model group(1.03±0.13,1.24±0.12,0.91±0.10,t=2.891,3.012,2.895,P<0.05).Conclusion Adenosine A2A receptor agonist(CGS21680)can significantly improve oxidative stress and inflammatory factors,reduce endoplasmic reticulum stress,reduce cardiomyocyte apoptosis and protect cardiomyocyte function.