K_(ATP)通道参与介导地氟醚对缺氧/复氧心肌细胞损害的保护作用

Myocardial protection by desflurane from anoxia/reoxygenation injury via activation of K_(ATP) channels

目的 研究 KATP通道在地氟醚对缺氧 /复氧心肌细胞损害保护中的作用。方法 原代培养乳鼠心肌细胞 ,随机分为 4组 :A组正常对照 ;B组单纯缺氧 /复氧 (缺氧 2 h复氧 1h) ;C组 9%地氟醚预处理 2 0 min后 ,进行缺氧 /复氧 ;D组地氟醚预处理前培养液中加入终浓度为 12μg/ m l KATP通道阻断剂优降糖。分别于复氧 2 0 m in和 6 0 min进行测定 :培养液乳酸脱氢酶 (L DH )和肌酸激酶 (CK )活性 ,细胞内 ATP和丙二醛 (MDA)含量 ,细胞存活率和凋亡率 ,细胞内游离 Ca2 + 浓度。结果 单纯缺氧 /复氧使 L DH、CK和 MDA水平和细胞凋亡率显著升高 (P<0 .0 1) ,细胞存活率和 ATP含量显著下降 (P<0 .0 1)。地氟醚预处理后明显减轻上述变化 (P<0 .0 1或 0 .0 5 ) ,优降糖部分取消地氟醚的减轻作用 ,其中 MDA升高达单纯缺氧 /复氧组水平 ,而对 ATP和 CK水平无明显影响。与正常对照组比 ,复氧 2 0 min其余三组细胞内游离 Ca2 + 浓度显著升高 (P<0 .0 1或 0 .0 5 ) ,但地氟醚预处理组升高幅度明显低于其它两组 (P<0 .0 5 ) ;复氧后 6 0 min各组均明显下降 ,其中地氟醚预处理组降至近正常组水平。结论 KATP通道参与介导地氟醚的心肌保护 ,并主要通过降低细胞内 Ca2 +

Objective To evaluate the roles of K ATP channels in desflurane-induced myocardial protection from anoxia/reoxygenation injury Methods Primary cultured rat myocardial cells were randomly allocated to four groups: control group(A): without any treatment; anoxia/reoxygenation group(B): reoxygenation of 1 h following anoxia of 2 h; desflurane preconditioning group(C): 20 min of 9% desflurane preconditioning followed by 10 min washout before anoxia/reoxygenation and K ATP channel blocker group(D): adding glybenclamide at final concentration of 12μg/ml to culture medium 10 min before the same procedures as group C The activities of lactic dehydrogenase (LDH) and creatine kinase (CK), rates of cell viability and apoptosis, contents of cellular malondiadehyde (MDA) and adenosine triphosphate (ATP), and intracellular free calcium concentration were measured Results Compared with control group, anoxia/reoxygenation caused great increases of levels of LDH, CK, apoptosis and MDA ,and decreases of ATP and cell viability (P<001 or 005) Desflurane preconditioning significantly attenuated these increases and decreases Glybenclamide partly abolished the effects of desflurane preconditioning except for ATP and CK Twenty min after reoxygenation, intracellular free Ca 2+ level was greatly increased in group B,C and D compared with in group A(P<001 or 005), and the level in group C was much lower than that in group B or D(P<005) ,and 60 min after reoxygenation, the Ca 2+ level in group C was decreased near to that in group AConclusions Activation of K ATP channels mediate desflurane preconditioning-induced myocardial preotection from anoxia/reoxygenation injury, mainly via reducing intracellular Ca 2+ overload and lipoid hyperoxidation