摘要
目的:观察卡托普利晚期预处理对缺氧/复氧乳鼠心室肌细胞游离钙的影响及其离子通道机制。方法:建立培养乳鼠心肌细胞缺氧/复氧损伤模型。设正常对照组、缺氧/复氧组、缺氧预适应组和卡托普利组。经Flou-3/AM负载染色后,采用流式细胞分析技术,测定细胞内钙离子浓度([Ca2+]i);利用膜片钳技术,观察L-型钙通道和钠钙交换电流的变化。结果:(1)缺氧/复氧时,[Ca2+]i和Na+/Ca2+交换电流高于正常对照组(P<0.01),L-型钙电流(ICa-L)峰值下降,I-V曲线上移,半数失活电压(V0.5)减小,ICa-L失活曲线左移。(2)晚期预处理和卡托普利使缺氧/复氧时[Ca2+]i低于缺氧/复氧组(P<0.01);ICa-L增加,I-V曲线下移,V0.5增大及稳态失活曲线右移;Na+/Ca2+交换电流减少;但[Ca2+]i和Na+/Ca2+交换电流高于对照组(P<0.05)。(3)卡托普利组与缺氧预适应组比较上述指标均无显著差异。结论:心肌细胞缺氧/复氧,通过Na+/Ca2+交换电流的异常增加可引起[Ca2+]i的异常升高及其钙超载;卡托普利通过轻度增加Na+/Ca2+交换电流及其[Ca2+]i而触发晚期预处理,抑制后续缺氧/复氧引起的Na+/Ca2+交换电流及其[Ca2+]i的异常增加。
AIM： To observe the influence of captopril on intracellular free calcium concentration （ [ Ca^2＋ ] i） and the involved ion channels mechanisms in cardiac myocytes of the neonatal rat undergone anoxia - reoxygenation injury. METHODS： The anoxia- reoxygenation model in cultured neonatal rat ventricular myocytes was established. Groups were divided into ①normal; ②anoxia- reoxygenation; ③anoxia- preconditioning （5 min anoxia ＋ 5 min reoxygenation） ; ④ captopril preconditioning. Flou - 3/AM loading and flow cytometry technique were used to observe the [ Ca^2＋ ] i, and whole - cell patch clamp technique was used to record the L - type calcium current and Na^＋/Ca^2＋ exchange current. RESULTS ： ① Compared to normal group, [Ca^2＋ ] i in anoxia - reoxygenation group was increased significantly （ 789. 42 ± 9. 05 vs 414.08 ± 37.40, P 〈 0. 01 ） , L - type calcium current density was decreased （ P 〈 0. 01 ） , the current - voltage curve was moved up, the inactivation curve was moved left and Na^＋/Ca^2＋ exchange current was increased in anoxia -deoxygenating. ② Compared to anoxia - reoxygenation group, anoxia and captopril preconditioning resulted in a significant decrease in [Ca^2＋ ]i （593.84 ±5.06, 507. 08 ±31.89 vs 789.42 ±9.05, P 〈0. 01 ） , and a significant increase in L - type calcium current density （P 〈 0. 01 ） , the current -voltage curve was moved down, the inactivation curve was moved right and Na^＋/Ca^2＋ exchange current was decreased ③ Compared to normal oxygen condition, the anoxia and captopril precondition resulted in a lightly increase in [ Ca^2＋]i （507.08 ± 31.89 vs 414.08 ± 37.40, P 〈 0.05） and Na^＋/Ca^2＋ exchange current. ④Compared to anoxia - preconditioning group, eaptopril - preconditioning resulted in no significant difference in all the markers mentioned above. CONCLUSIONS： The anoxia- reoxygenation injury in cardiac myocytes results in [Ca^2＋]i abnormal increase and calcium overload by increasing Na^＋/Ca^2＋ exchange current. Late preconditioning in cardiac myocytes is triggered by transient and repeated anoxia and captopril, which slightly increases Na^＋/Ca^2＋ exchange current and [ Ca^2＋ ]i and restraines the abnormal increasing of Na^＋/Ca^2＋ exchange current and calcium overload induced by subsequenced anoxia - reoxygenation injury, so it plays an delayed protective role in cardiac myocytes. L- typed calcium passage is not involved in calcium overloaded and late preconditioning of calcium in myocytes during reperfusion.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2006年第9期1693-1697,共5页
Chinese Journal of Pathophysiology
基金
吉林省科技发展计划项目资助(No.吉发合字990581-1)
关键词
卡托普利
钙通道
L型
心肌细胞
缺氧
Captopril
Calcium channels, L - type
Cardiomyocytes
Anoxia
