哇巴因与地高辛对大鼠肾脏皮质钠泵α亚单位基因表达的影响

目的　对比研究哇巴因与地高辛对大鼠肾脏皮质钠泵 (Na+ ,K+ ATP酶 )α亚单位基因表达的影响 ,探讨内源性哇巴因 (EO)的生物学效应以及洋地黄类药物药理作用的分子机制。方法　长期给予大鼠注射小剂量哇巴因 (2 0 μg·kg- 1·d- 1)与地高辛 (32 μg·kg- 1·d- 1) ,动态观察大鼠血压变化 ;分别应用分子生物学RT PCR及免疫组织化学技术 ,研究各组大鼠肾脏皮质钠泵α1、α2及α3亚单位mRNA及蛋白水平基因表达的改变。结果　哇巴因与地高辛对大鼠血压的影响存在着明显差别 ,长期给予大鼠注射小剂量哇巴因可使大鼠血压升高 ,而地高辛对大鼠血压无影响。但哇巴因与地高辛对大鼠肾脏皮质钠泵α亚单位基因表达的影响是相同的 ,在mRNA水平均可使α1亚单位表达增强 ,α2与α3亚单位表达无改变 ;而在蛋白水平α1亚单位表达减弱 ,α3亚单位表达增强 ,α2亚单位表达无改变。结论　哇巴因在高血压发病中可能起着重要作用 ;哇巴因与地高辛可导致相同的肾脏皮质钠泵基因表达改变 ,提示这种表达的改变在哇巴因导致血压升高的过程中可能并不起着关键性作用。

Differential regulation of sodium pmnp a-subunit isoform gene by ouabain and digoxin in kidney of rats

ObjectiveTo compare the effects of ouabain an d digoxin on both the systolic blood pressure(SBP) and sodium pump ~{&A~} subunit ex pression in the cortex of kidney of rats.MethodsNormal Spr agueDawley(SD) rats were respectively injected with ouabain,digoxin and normal saline(NS) everyday and indirect SBP were recorded once a week. Six weeks later ,all the rats were killed and sodium pump ~{&A*-~}1,~{&A*-~}2,and ~{&A*-~}3subunit were detected in the cortex of kidney with RTPCR method and immunohistochemica l assay at mRNA and protein levels,respectively.ResultsSBP of rats infused with ouabain increased significantly at the end of week 6 ~{!2~} (132.6 ~{!@~} 9.0) vs (115.7~{!@~}8.2) mmHg, ~{*+~}P~{*+~}<0.01~{!3~},while no difference of SBP was found be twe en digoxin group and NS group. On the other hand,digoxin had the same effect on sodium pump isoform expression in the cortex of kidney as ouabain.~{&A*-~}1isoform increased but ~{&A*-~}2and ~{&A*-~}3isoforms unchanged at mRNA level,while ~{&A*-~}1 isofo rm decreased and ~{&A*-~}3isoform increased at protein level.Conclusion~{!~~} Those results suggest that both ouabain and digoxin can regulate the sod ium pump ~{&A*2~}subunit isoform expression,which may be related to the physiologica l roles of endogenous ouabain and might be responsible for the pharmacological a nd toxicological effects of digitalis drugs.