低氧降低大鼠肺动脉平滑肌细胞Kv1.5通道表达的p38MAPK通路机制

目的 探讨低氧对肺细小动脉平滑肌细胞Kv1.5通道表达的影响及其与p38 MAPK通路的关系,明确低氧性肺动脉高压（HPH）的发病机制.方法 SPF级雄性SD大鼠,超净工作台内分离3～4级肺动脉平滑肌细胞（PASMCs）.采用p38MAPK通路抑制剂SB203580和激活剂茴香霉素干预低氧过程.细胞传至3～6代后随机分为5组：正常对照组（N）,低氧组（H）,低氧＋ DMSO组（HD）,低氧＋SB203580组（HS）,低氧＋茴香霉素组（HA）,其中N组继续5％ CO2培养箱培养.其他组于低氧培养箱培养（5％ CO2,2％O2,PO2：25 ～ 35mmHg）,均培养60h.采用RT-PCR法测定PASMCs Kv1.5 mRNA含量,采用Western blot法测定PASMCs Kv1.5蛋白含量.结果 与N组相比,H组、HD组、HA组Kv1.5mRNA和蛋白表达均明显降低（P＜0.05）.较之H组和HD组,HS组Kv1.5 mRNA和蛋白表达明显上升,差异有统计学意义（P＜0.01）,H组和HD组间差异无统计学意义（P＞0.05）,与HS组相比,HA组Kv1.5mRNA和蛋白表达明显降低（P＜0.01）.结论 低氧通过激活p38 MAPK信号通路降低Kv1.5通道表达,这可能是（HPH）的发病机制.

Decreased Kv1.5 Channel of Pulmonary Artery Smooth Muscle Cell by the p38MAPK Signaling Pathway in Hypoxia

Objective To explore the effect of p38MAPK signaling pathway on Kv1.5 channel in the process of hypoxia.Methods The SPF male Sprague-Dawley rats were used.The third or fourth division of pulmonary artery was separated in order to obtain single PASMC.The inhibitor and activator of p38MAPK signaling pathway SB203580 and anisomycin were involved in hypoxia.Cultured for 3-6 generations,the PASMCs were randomly divided into five groups：normal group （N）,hypoxia group （H）,DMSO control group （HD）,SB203580 group （HS）,anisomycin group（HA）.Then,group N was continued to be cultured in 5 % CO2 incubator,other groups were to be cultured in hypoxic incubator （5% CO2,2% O2,PO2：25-35mmHg）.All cells were cultured for 60 hours.RT-PCR was used to detect the expression of PASMCs Kv1.5mRNA.Western Blot was used to detect the expression of PASMCs Kv1.5 protein.Results Compared with N group,the expression of Kv1.5mRNA and protein in H group,HD group and HA group were significantly reduced （P 〈0.05）.Compared with H group and HD group,the expression Kv1.5 mRNA and protein in HS group were increased sharply,and the difference was significant （P 〈 0.01）,no significant difference between H group and HD group （P 〉 0.05）.Compared with the HS group,Kv1.5 mRNA and protein in HA group were significantly lower （P 〈 0.01）.Conclusion Hypoxia down-regulates the mRNA and protein expression of Kv1.5 channels by activating p38 MAPK signaling pathway,which may be the pathogenesis of HPH.