低氧对大鼠肺动脉平滑肌细胞中Gax基因表达及细胞增殖的影响

Effects of hypoxia on Gax gene expression and proliferation of rat pulmonary artery smooth muscle cells

目的探讨低氧对肺动脉平滑肌细胞(pulmonary artery smooth muscle cells,PASMCs)中生长终止特异性同源盒(growth arrest-spec ific homeobox,Gax)基因表达及细胞增殖的影响。方法以RT-PCR法、免疫细胞化学法和W estern blot法测定经低氧处理后的大鼠PASMCs中Gax mRNA和蛋白表达3。H-TdR掺入法观察低氧处理后PASMCs增殖情况。结果RT-PCR、免疫细胞化学和W estern blot检测证实低氧(2.5%O2)处理后的PASMCs中Gax mRNA和蛋白的表达逐渐降低;与常氧组比较,低氧组Gax mRNA和蛋白的表达显著下降3。H-TdR掺入法测定结果示PASMCs3H-TdR掺入量在低氧6 h开始增加,随着低氧时间延长,3H-TdR掺入量逐渐增加,至低氧24 h时3H-TdR掺入量最高。结论低氧可下调大鼠PASMCs中Gax mRNA和蛋白的表达并诱导PASMCs增殖,提示Gax基因在低氧性PASMCs增殖过程中可能起着重要作用。

Objective To explore the effects of hypoxia on the expression of Gax gene and proliferation of rat pulmonary arterial smooth muscle cells （PASMCs）. Methods Under hypoxia （2.5%O2 ） condition, the expression of Gax mRNA and protein in PASMCs of rat was detected by RT-PCR, immunocytochemistry and Western blotting. ^3H-TdR incorporation was used to observe the PASMCs proliferation. Results The expression of Gax mRNA and protein in PASMCs treated by hypoxia was confirmed to decrease by RT-PCR, immunocytochemistry and Western blotting. Compared with that in the control group, Gax mRNA and protein level decreased significantly in hypoxia PASMCs. With prolongation of time of hypoxia,^3H-TdR incorporation in PASMCs was significantly higher at 6 h, and reached a maximum at 24 h. Conclusion Hypoxia can downregulate the expression of Gax mRNA and protein in PASMCs and induce PASMCs proliferation, implying that Gax gene might play an important role in hypoxia-induced PASMCs proliferation.