羟考酮预先给药对大鼠心肌缺血再灌注损伤的影响及其与PI3K/Akt信号通路的关系

Effect of oxycodone pretreatment on myocardial ischemia-reperfusion injury in rats and its relationship with PI3K/Akt signaling pathway

目的 评价羟考酮预先给药对大鼠心肌缺血再灌注损伤的影响及其与磷脂酰肌醇3-激酶/丝氨酸-苏氨酸蛋白激酶（PI3K/Akt）信号通路的关系.方法 健康雄性SD大鼠48只,7～8周龄,体重250～ 320 g,采用随机数字表法分为4组（n=12）：假手术组（S组）、缺血再灌注组（I/R组）、羟考酮预先给药组（OP组）和PI3K/Akt信号通路阻断剂LY204002组（LY组）.I/R组、OP组和LY组采用结扎左冠状动脉前降支30 min,再灌注120 min的方法制备大鼠心肌缺血再灌注损伤模型,S组只穿线,不结扎左冠状动脉前降支.于再灌注前5 min时OP组和LY组颈内静脉注射羟考酮注射液0.5 mg/kg,S组和I/R组颈内静脉注射等容量生理盐水.LY组于羟考酮给药前30 min时腹腔注射LY294002 1.4 mg/kg.再灌注120 min时,心脏采血样,测定血清CK-MB和cTnI的浓度,然后处死大鼠,取心肌组织,确定心肌梗死体积,光镜下观察病理学结果,采用免疫组化法测定Bcl-2和Bax的表达水平,并计算Bcl-2/Bax比值.结果 与S组比较,I/R组、OP组和LY组血清CK-MB和cTnI的浓度升高,心肌梗死体积升高,心肌组织Bcl-2和Bax的表达上调,Bcl-2/Bax比值降低（P＜0.05）;与I/R组比较,OP组和LY组血清CK-MB和cTnI的浓度降低,心肌梗死体积降低,心肌组织Bcl-2表达上调,Bax表达下调,Bcl-2/Bax比值升高（P＜0.05）,病理学损伤减轻;与OP组比较,LY组血清CK-MB和cTnI的浓度升高,心肌梗死体积升高,心肌组织Bcl-2表达下调,Bax表达上调,Bcl-2/Bax比值降低（P＜0.05）,病理学损伤加重.结论 羟考酮预先给药可减轻大鼠心肌缺血再灌注损伤,其机制与激活PI3K/Akt信号通路,抑制心肌细胞凋亡有关.

Objective To evaluate the effect of oxycodone pretreatment on myocardial ischemiareperfusion （I/R） injury in rats and its relationship with phosphatidylinositol 3-kinase/serine-threonine kinase （PI3K/Akt） signaling pathway.Methods Forty-eight healthy male Sprague-Dawley rats,aged 7-8 weeks,weighing 250-320 g,were randomly divided into 4 groups （n=12 each） using a random number table：sham operation group （group S）;group I/R;oxycodone pretreatment group （group OP）;LY204002 （PI3K/Akt signaling pathway blocker） group （group LY）.Myocardial ischemia was induced by 30 min occlusion of the left anterior descending branch of the coronary artery,followed by 120 min reperfusion in I/R,OP and LY groups.In group S,the anterior descending branch was only exposed but not ligated.Oxycodone injection 0.5 mg/kg was injected via the internal jugular vein at 5 min before reperfusion in OP and LY groups,respectively,while the equal volume of normal saline was injected via the internal jugular vein at 5 min before reperfusion in S and I/R groups.LY294002 1.4 mg/kg was injected intraperitoneally at 30 min before oxycodone administration in group LY.At 120 min of reperfusion,blood samples were collected from the hearts for determination of creatine kinase-MB （CK-MB） and cardiac troponin Ⅰ （cTnI） concentrations in serum.The animals were then sacrificed,and myocardial specimens were obtained for measurement of myocardial infarct size （IS）,for examination of pathological changes （with light microscope）,and for determination of the expression of Bcl-2 and Bax （by immunohistochemistry）.Bcl-2/ Bax ratio was calculated.Results Compared with group S,the serum CK-MB and cTnI concentrations were significantly increased,the myocardial IS was significantly increased,the expression of Bcl-2 and Bax was significantly up-regulated,and the Bcl-2/Bax ratio was significantly decreased in I/R,OP and LY groups （P〈0.05）.Compared with group I/R,the serum CK-MB and cTnI concentrations were significantly decreased,the myocardial IS was significantly decreased,Bcl-2 expression was significantly up-regulated,Bax expression was significantly down-regulated,the Bcl-2/Bax ratio was significantly increased （P 〈 0.05）,and the pathological changes were attenuated in OP and LY groups.Compared with group OP,the serum CK-MB and cTnI concentrations were significantly increased,the myocardial IS was significantly increased,Bcl-2 expression was significantly down-regulated,Bax expression was significantly up-regulated,the Bcl-2/Bax ratio was significantly decreased （P〈0.05）,and the pathological changes were aggravated in group LY.Conclusion Oxycodone pretreatment can mitigate myocardial I/R injury in rats,and the mechanism is associated with activation of PI3K/Akt signaling pathway and inhibition of apoptosis in cardiomyocytes.