酸敏感离子通道1α介导缺氧皮质神经元损伤及相关机制的探讨

Cortical neuronal injury by hypoxia mediated through acid-sensing ion channel 1α and its mechanism

目的探讨缺氧条件下阻断酸敏感离子通道1α(acid sensing ion channels 1α,ASIC1α)对大鼠皮质神经元存活及细胞内钙离子水平的影响,以及缺氧对皮质神经元ASIC1表达的影响。方法通过使用ASIC1α阻断剂、N甲基D门冬氨酸(NMDA)受体阻断剂、电压门控通道阻断剂,利用fura-3/AM荧光显像,乳酸脱氢酶(lactate dehydrogenase,LDH)释放实验等技术,比较观察对缺氧皮质神经元存活以及钙离子水平的影响,进一步利用Western印迹法检测ASIC1的表达变化。结果酸性环境中,缺氧皮质神经元形态明显改变,细胞内钙离子浓度升高;与加入NMDA受体阻断剂、电压门控通道阻断剂相比较,加入ASIC1α阻断剂明显抑制细胞内钙离子水平升高(P<0.05),对神经元起到保护作用。随缺氧时间的延长,神经元ASIC1蛋白表达增加。结论酸性环境中,缺氧皮质神经元的损伤与ASIC1α开放以及表达增加有关;阻断ASIC1α具有神经保护作用。

Objective To investigate the effects of acid-sensing ion channel 1αon cortical neuronal survival rate under hypoxia and its intraeellular calcium level ,and the effect of cortical neuron under hypoxia on ASIC1α expression. Methods The variation of survival rate and calcium concentration in cortical neuronal injury by hypoxia were measured via LDH release and fura -3/AM in the presence of antagonists of ASIC1α,NMDA and voltage-gated Ca^2＋ channels. Expression of ASIC1 was also detected through Western blot. Results Swelling and cell death occurred after hypoxia treatment and the level of intraeellular calcium significantly increased. In comparison with the effect of voltage-gated Ca^2＋ channel and NMDA blockers,the blockade of ASIC1α could reduce the concentration of intraeellular calcium （P〈0. 05） and protect the neurons. Expression of ASIC1 also increased as hypoxia impairment developed,which was in positive correlation with the dynamics of cell apoptosis. Conclusion The mechanisms of cultured rat cortical neurons injure by hypoxia may be involved by the opening and up-regulation of ASIC1α. Blocking ASIC1α plays a neuroproteetive role.