Ⅰ型Na^+/H^+交换器在LPS引起的大鼠肺微血管内皮细胞损伤中的作用

Role of Na^+/H^+ exchanger 1 in lipopolysaccharide-induced injury of rat pulmonary microvascular endothelial cells

目的探索Ⅰ型Na+/H+交换器(NHE1)在脂多糖(LPS)引起的大鼠肺微血管内皮细胞(PMVECs)损伤中的作用。方法培养大鼠PMVECs。MTT比色试验检测细胞活力;比色法测试上清液中乳酸脱氢酶(LDH)活力和丙二醛(MDA)浓度;BECEF-AM荧光探针染色细胞,激光共聚焦显微镜下观察细胞内酸碱度,检测NHE1的活性;PT-PCR技术检测NHE1的mRNA表达。结果LPS不仅使细胞活力降低35%(P<0.05),使上清液中LDH和MDA分别升高3倍和2.5倍(P<0.05),而且使NHE1的活性增强,mRNA表达增多(P<0.05)。但是NHE1的抑制剂———环己阿米洛利(HMA)能显著抑制LPS引起的这些变化(P<0.05)。结论NHE1的活性增强和表达增多是LPS引起大鼠PMVECs损伤的重要机制。

Objective To explore the role of Na^＋/H^＋ exchangers 1 （NHE1） in lipopolysaccharide （LPS）- induced injury of rat pulmonary microvascular endothelial cells （PMVECs）. Methods Cultured rat PMVECs. Cells viability was examined by MTT assay. The LDH activity and MDA production from supernatants were examined by colorimerry. After cells were stained by BECEF-AM fluorescent probe, intracellular pH was measured by confocal microscopy. Expression of NHE1 mRNA was evaluated by RT-PCR. Results LPS significantly attenuated cells viability by 65 %, and increased LDH activity and MDA production by 3 times and 2. 5 times respectively （P 〈 0. 05 ）. Moreover, LPS also increased NHE1 activity and mRNA expression （P 〈 0. 05 ）. On the contrary, 5- （N, N-hexamethylene）-amiloride （HMA, NHE1 inhibitor） could suppress these changes induced by LPS significantly （P 〈 0.05 ）. Conclusion The increase of NHE1 activity and expression are the important mechanisms of LPS- induces injury of rat PMVECs.