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目的:探讨棕榈酸激活上皮细胞钠通道(epithelial sodium channel,ENa C)的分子机制,以及H_2S对抗棕榈酸引起的ENa C异常激活的作用和机制。方法:应用肾皮质集合管上皮细胞,采用膜片钳技术研究H_2S对抗棕榈酸引起ENa C异常激活的保护作用和分子机制;应用激光共聚焦显微镜技术观察棕榈酸能否调节细胞内钙水平和细胞内ROS水平变化。结果:棕榈酸引起的细胞ENa C活性升高可以被Na HS抑制;棕榈酸引起的细胞内ROS水平升高可以被Na HS抑制,且应用NADPH抑制剂APO可以抑制棕榈酸引起的ENa C活性升高;棕榈酸可以引起细胞内钙的升高;应用钙离子螯合剂BAPTA/AM或IP3受体抑制剂APB可以抑制棕榈酸引起的ENa C活性升高;胰岛素受体抑制剂HNMPA和PI3K抑制剂LY204002也可以抑制棕榈酸引起的ENa C活性升高;DTT可以模拟Na HS对棕榈酸引起ENa C异常激活的保护作用。结论:棕榈酸通过诱导胰岛素受体磷酸化,引起细胞内钙释放,进而激活NADPH升高细胞内活性氧水平,引起ENa C异常激活。气体信号分子H_2S通过氧化还原反应抑制棕榈酸引起的ENa C异常激活。
OBJECTIVE: To investigate the molecular mechanism of palmitate in activating epithelial sodium channel (ENaC) and the role of H 2 S in antagonizing the abnormal activation of ENa C induced by palmitate. Methods: The renal cortex collecting duct epithelial cells were used to study the protective effect and molecular mechanism of H 2 S against palmitate-induced abnormal activation of ENa C. Patch clamp technique was used to observe whether palmitic acid can regulate intracellular calcium levels and cells Changes in ROS levels. Results: The increase of intracellular ENaC activity induced by palmitate could be inhibited by Na HS; the intracellular ROS level induced by palmitate could be inhibited by Na HS; and the NADPH inhibitor APO could inhibit the increase of ENa C activity induced by palmitate High; palmitic acid can cause intracellular calcium increased; application of calcium ion chelator BAPTA / AM or IP3 receptor inhibitor APB can inhibit palmitic acid-induced ENa C activity increased; insulin receptor inhibitors HNMPA and PI3K inhibitors LY204002 also inhibited the increase of ENa C activity induced by palmitic acid. DTT could simulate the protective effect of Na HS on the abnormal activation of ENa C induced by palmitate. CONCLUSION: Palmitic acid induces intracellular calcium release by inducing insulin receptor phosphorylation, which in turn activates NADPH to increase intracellular reactive oxygen species and cause abnormal activation of ENa C. Gas signaling molecule H_2S inhibits the abnormal activation of ENa C induced by palmitate through the redox reaction.