容量敏感外向整流性氯通道参与氧化应激介导的系膜细胞凋亡

目的 探讨容量敏感外向整流性(VSOR)氯通道在H2O2介导系膜细胞凋亡中的作用和可能的机制。 方法 全细胞膜片钳技术用于检测VSOR氯电流。细胞凋亡通过吖啶橙/溴化乙锭荧光染色、电子显微镜、TUNEL染色和半胱氨酸天冬氨酸蛋白酶(caspase)-3活性确定。 结果 150 μmol/L H2O2激活系膜细胞VSOR氯电流，H2O2激活的氯电流具有典型的VSOR氯电流电生理特性，包括：外向整流性、电压依赖性失活。对细胞外高渗透压敏感及被VSOR氯通道阻断剂抑制。VSOR氯通道阻断剂DIDS(100 μmol/L)，NPPB(10 μmol/L)和尼氟灭酸(10 μmol/L)明显抑制H2O2介导的系膜细胞凋亡。150 μmol/L H2O2处理2 h内，细胞容量明显下降，但这种细胞容量下降被100 μmol/L DIDS，10 μmol/L NPPB和10 μmol/L尼氟灭酸抑制。结论 VSOR氯通道参与H2O2介导的系膜细胞凋亡，其机制与介导凋亡性容量下降有关。

Volume-sensitive outwardly rectifying chloride channels are involved in oxidative stress-induced apoptosis of mesangial cells

Objective To investigate the role of volume-sensitive outwardly rectifying (VSOR) chloride channels in mesangial cell apoptosis induced by H2O2. Methods VSOR chloride current was recorded in whole cell configuration. The apoptosis was evaluated by AO/EB staining， transmission electron microscopy， TUNEL staining and caspase-3 activity. Cell volume was measured by Lag-time microphotography. Results Application of 150 μmol/L H2O2 led to activation of VSOR Cl- conductance in mesangial cells. H2O2-induced Cl- current showed phynotypical properties of VSOR Cl- channels， including outward rectification， voltage-dependant inactivation at large positive potentials， sensitiveness to hyperosmolarity，inhibition by VSOR Cl- channel blockers. Moreover， blockage of VSOR Cl- by DIDS(100 μmol/L)， NPPB(10 μmol/L) or niflumic acid(10 μmol/L) rescued mesangial cells from H2O2-induced apoptotic cell death. Treatment for 2 hours with 150 μmol/L H2O2 resulted in significant reduction in cell volume. However， the early-phase alterations in cell volume were markedly abolished by pretreatment with VSOR Cl- channel blockers. Conclusion VSOR Cl- channels are involved in H2O2-induced apoptosis of mesangial cells and its mechanism is associated with the decrease of apoptotic volume (AVD).