氯离子参与心肌细胞缺氧复氧损伤机制的研究

目的研究氯离子参加心肌细胞缺氧/复氧(A/R)损伤的机制。方法采用原代培养新生大鼠的心肌细胞A/R损伤模型,去除细胞外的氯离子(Cl--free),或分别给予Na+-K+-2Cl-共同转运体阻断剂bumetanide,Cl-/HCO3-离子交换系统抑制剂SITS和氯通道阻断剂9-AC,观察细胞存活率、MDA含量、LDH、SOD、GSH-Px酶活性变化及细胞内的钙含量、NF-κB活性变化。结果A/R组与对照组比,MDA含量、LDH活性、细胞内的钙含量、NF-κB活性升高,细胞存活率、SOD、GSH-Px活性降低;bumetanide及9-AC组与A/R组比,各项指标无统计学意义。Cl--free、SITS处理后较A/R组,MDA含量、LDH活性、细胞内的钙含量、NF-κB活性降低,而细胞存活率、SOD、GSH-Px明显升高。结论Cl-/HCO3-离子交换系统在心肌细胞A/R损伤中起了重要作用,Cl-参与心肌A/R损伤的机制与钙超载及NF-κB活性升高有关。

Mechanisms of chloride in anoxia-reoxygenation injury of cultured rat ventricular myocytes

Aim To study the role and mechanisms of chloride in anoxia-reoxygenation injury of primary cultured rat ventricular myocytes. Methods Under conditions of anoxia- reoxygenation(A/R) injury, primary cultured rat ventricular myocytes were treated with Cl-/HCO3- inhibitor 4-acetanide-4′-isothiocya- natostilbene -2,2′-disulfonic acid (SITS), Cl- channel blocker Anthracene-9-carboxylic acid(9-AC),Na+,K+-2Cl- inhibitor bumetanide or replaced Cl- with equimolar gluconate, respectively. The cell viability and contents of malondialdehyde(MDA) and intracellular Ca2+(Ca2+]i),activity of Lactate dehydrogenase (LDH), superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)and Nuclear factor kappa-B (NF-κB) were measured. Results After reoxygenation, contents of MDA and Ca2+]i, activity of NFκB were significantly increased in the A/R group while the cell viability and activities of LDH, SOD, GSH-Px decreased compared with those of control group. The cell viability and contents of MDA, LDH, SOD and GSH-Px in 9-AC or bumetanide group had no significance compared with those of A/R group. In Cl--free group or SITS group, contents of MDA and Ca2+]i , activity of NF-κB were noticeably lower than those of the A/R group while the cell viability and activities of SOD, GSH-Px significantly increased compared with those of A/R group. Conclusions The A/R induced Cl- increase is mediated by anion exchange stimulation, and Cl- increase takes part in the reoxygenation induced Ca2+ overload as well as NF-κB transposition.