地氟烷预处理对幼鼠心肌细胞血管紧张素受体Ⅰ型表达的影响

Effect of desflurane pretreatment on the expression of angiotensin Ⅰ receptor on rat cardlomyocytes subjected to hypoxia-reoxygenation

目的 观察地氟烷预处理对缺氧,复氧心肌细胞血管紧张素受体Ⅰ型(AT1受体)表达的影响。方法无菌取新生2—3 d的SD幼鼠心室,采用胰蛋白酶消化成散在的单个细胞。加入DMEM培养液培养至第7天。随机分为四组,组1:细胞不经任何处理;组2:缺氧2 h,复氧1 h;组3:1.5 MAC地氟烷预处理20 min,清洗10 min,其余处理同组2;组4:地氟烷预处理前5 min,培养液中加入AT1受体阻断剂洛沙坦(Losartan),终浓度为10-6mol/L。比色法测培养液中肌酸激酶(CK)、乳酸脱氢酶(LDH)活性;Rt-PCR测各组细胞AT1受体的基因表达(mRNA)。结果 组2CK、LDH活性及AT1受体mRNA的相对含量均高于组1(P<0.01);组3 CK、LDH活性及AT1受体mRNA均降低(与组2和组1比较,P<0.01);组4与组3比较CK、LDH活性及AT1受体mRNA的相对含量上升(P<0.05或0.01),但仍低于组2(P<0.01)。结论 地氟烷预处理可部分逆转缺氧/复氧所致的心肌细胞损伤,其保护效应的发生机制部分由AT1受体介导。

Objective To investigate if angiotensin Ⅰ (AT Ⅰ ) receptor is involved in the cardioprotective effect of desflurane preconditioning. Methods SD rats aged 2-3 days were used in this study. Cardiomyocytes were obtained from ventricle after digestion with trypsin and cultured in DMEM medium. Cardiomyocytes cultured for 7 days were divided into 4 groups : group Ⅰ control; group Ⅱ hypoxia-reoxygenation; group Ⅲ desflurane preconditioning and group Ⅳ AT Ⅰ receptor blocker-losartan. In control group the myocytes received no special treatment of any kind. In group Ⅱ myocyte culture flask was placed in a tightly closed sterile container filled with 95 % N2 + 5 % C02 at 37 ℃ for 2 h followed by 1 h reoxygenation. In group Ⅲ the myocytes were exposed to 9 % desflurane for 20 min before 2 h hypoxia and 1 h reoxygenation. In group Ⅳ AT Ⅰ receptor blocker losartan was added to the medium (final concentration = 10-6 mol·L-1 ) 5 min before desflurane preconditioning. The culture medium creatine kinase (CK) and lactic dehydrogenase (LDH) concentrations were measured using colorimetry ATI receptor expression was quantified by RT-PCR.Results The CK, LDH concentrations were greatly increased by hypoxia-reoxygenation (H-R) in group Ⅱ as compared with group Ⅰ (control group) (P < 0.01) . Desflurane preconditioning significantly inhibited the increase in CK, LDH concentrations induced by H-R and AT I receptor blocker losartan partly antagonized the protective effect of desflurane preconditioning on myocytes against H-R injury. The expression of AT I receptor was significantly increased in group Ⅱ compared with that in control group. Desflurane preconditioning significantly inhibited the increase in AT Ⅰ receptor expression induced by H-R injury and losartan antagonized the protective effect of desflurane. Conclusion Desflurane pretreatment can partly protect the Cardiomyocytes from hypoxia-reoxygenation injury by blocking AT Ⅰ receptor.