慢性缺氧对大鼠肺内动脉平滑肌细胞Kv1.3、Kv2.1、Kv3.1钾通道基因在急性缺氧时表达的影响

Influences of chronic hypoxia on the gene expression of Kv1.3,Kv2.1 and Kv3.1 induced by acute hypoxia in PASMC of rats

目的与方法 :用半定量RT -PCR方法 ,研究慢性连代缺氧对大鼠肺内动脉平滑肌细胞 (PASMC)Kv1 3、Kv2 1、Kv3 1钾通道基因在急性缺氧时表达变化的影响。结果 :①正常及慢性缺氧鼠PASMC中均有Kv1 3、Kv2 1、Kv3 1基因表达 ;②急性缺氧可使PASMC中Kv2 1、Kv3 1mRNA表达明显上调 ,其mRNA分别由 0 6 4 6± 0 0 92、0 782± 0 10 4升高到 1 0 5 9± 0 134、0 985± 0 116 (P <0 0 1) ;③慢性缺氧后复氧 12h再急性缺氧 6h ,PASMCKv2 1mRNA、Kv3 1mRNA水平均降低 ,其中Kv2 1mRNA由 1 0 0 8± 0 117下降到 0 6 4 9± 0 0 97,差异有极显著意义 (P<0 0 1)。结论 :Kv2 1、Kv3 1基因可能是缺氧反应基因 ,慢性缺氧可改变PASMC的Kv2 1、Kv3 1钾通道基因对急性缺氧的反应 ,使其由表达上调转变为下调 ,可能因而降低此钾通道在HPV中的作用。

AIM and METHODS: Total RNA was extracted from 6th rat subcultured pulmonary artery smooth muscle cells(PASMC) exposed to continual chronic hypoxia or normoxia and the effects of chronic hypoxia on the changes of Kv1.3,Kv2.1,Kv3.1 mRNA in cultured PASMC induced by acute hypoxia were studied by semiquantitative RT-PCR in vitro. RESULTS:①Kv1.3,Kv2.1,Kv3.1 genes were found to be expressed in PASMC of rats exposed either to hypoxia or normxia.②The expression of Kv2.1 and Kv3.1 in 6th subcultured of PASMC in normaxia group could be upregulated by exposure to acute hypoxia,the levels of Kv2.1 and Kv3.1 mRNA were significantly increased from 0.646±0.092, 0.782±0.104 to 1.059±0.134, 0.985±0.116,respectively (P<0.01,n=5). ③PASMC cultured continuously in chronic hypoxia for 6 subcultures and then exposed to normoxia for 12 h,thereafter the expression of Kv2.1 and Kv3.1 were downregulated by acute hypoxia for 6 hours.The level of Kv2.1 mRNA was significantly decreased from 1.008±0.117 to 0.649±0.097 (P<0.01,n=5). CONCLUSION:Kv2.1,Kv3.1 genes might be oxygen sensitive genes.Chronic hypoxia might change the response of these Kv genes of PASMC to acute hypoxia and down-regulate its expression,which might probably decrease the role of Kv in HPV.