BQ123对大鼠肺动脉平滑肌细胞电压门控钾通道表达的影响

Effect of BQ123 on the expression of voltage-gated K^+ channel of rat pulmonary artery smooth muscle cells

目的:探讨内皮素-1受体拮抗剂BQ123对大鼠肺动脉平滑肌细胞电压门控钾通道亚型基因表达的影响。方法:根据常氧(PO2152mmHg)及慢性低氧(PO240±5mmHg)的不同培养条件,将肺动脉平滑肌细胞分为常氧组和慢性低氧组,并用BQ123分别处理上述两组细胞,采用半定量RT-PCR技术检测大鼠肺动脉平滑肌细胞Kv2·1、Kv9·3基因表达的变化。结果:经过慢性低氧,大鼠肺动脉平滑肌细胞Kv2·1、Kv9·3的mRNA表达水平明显低于常氧组(P<0·01,n=5),BQ123对常氧组Kv2·1的mRNA表达无影响(P>0·05,n=5),但可明显增加慢性低氧组Kv2·1的表达(P<0·01,n=5)。无论在常氧还是慢性低氧时,BQ123对Kv9·3的mRNA表达均无影响(P>0·05,n=5)。结论:慢性低氧可降低大鼠肺动脉平滑肌细胞电压门控钾通道的表达,内皮素-1受体拮抗剂BQ123可能通过抑制PASMCs的增殖,改变了细胞内信号转导通路中某些因子的表达,从而间接促进Kv的表达。

AIM： To elucidate the effect of ET-1 on the expression of vohage- gated K^＋ channel α subunits Kv2.1, Kv9.3 in pulmonary artery smooth muscle cells in rats. METHODS： The mRNA expression of Kv2.1, Kv9.3 in the 2nd, 3rd, 4th subculture of intrapulmonary artery smooth muscle cells isolated from Wistar rots, which exposed to either normoxia or chronic hypoxia, were detected with reverse transcription- PCR （RT- PCR）. At the same time, PASMCs were treated with BQ123, an ETA receptor antagonist. RESULTS： The expression of Kv2.1 and Kvg.3 gene were found in the subculture PASMCs of rats exposed either to normoxia or chronic hypoxia. Chronic hypoxia decreased mRNA expressions of Kv channel subunit Kv2.1, Kvg.3 in PASM- Cs from 0.827±0.126 and 0.388±0.026 to 0.378±0.015 and 0.184±0.009, respectively （P〈0.01, n = 5）. The level of mRNA of Kv2.1 in PASMCs exposed to chronic hypoxia was significantly upregulated after treatment with BQ123 （from 0.833 ± 0.175 to 0.794 ± 0.158, P 〈 0.01, n = 5）. BQ123 had no effect on the gene expression of Kvg. 3 in PASMCs exposed to both nonnoxia and chronic hypoxia. CONCLUSION： Chronic hypoxia downregulates gene transcription and expression of Kv channel subunits （ Kv2.1 and Kvg. 3 ）. BQ 1 23 increases, the expression of Kv2.1, but affects negligibly transcription of Kvg. 3, suggesting a potent therapeutic approach in the management of hypoxic pulmonary hypertension.