遗传高钙尿结石大鼠肾小管上皮细胞基底膜钙转运蛋白的异常表达及意义

Abnormal expression of Ca^2＋ active transport proteins on basolateral membrane of renal tubule epithelial cells in kidney of rats with genetic hypercalciuric stone-forming and implication

目的观察肾小管上皮细胞基底膜钙转运蛋白细胞膜钙泵1b（PMCA1b）和钠钙交换体1（NCX1）在遗传性高钙尿结石（GHS）大鼠肾组织的表达及其在特发性高钙尿症（IH）发病中的作用。方法雄性遗传高钙尿结石大鼠和正常野生型SD大鼠各6只，采用实时荧光定量PCR检测PMCA1b和NCX1 mRNA表达，Western blot方法检测其蛋白表达。结果GHS大鼠与正常对照（NC）组大鼠的NCX1在mRNA水平和蛋白水平比较差异均无统计学意义（P〉0．05）；GHS大鼠与NC大鼠的PMCA1b在mRNA水平比较差异无统计学意义（P〉0．05），GHS大鼠的PMCA1b蛋白平均相对吸光度值（A）为（0．18±0．05），NC组为（0．43±0．07），差异有统计学意义（P〈0．01）。结论PMCA1b蛋白表达下降可能是特发性高钙尿症形成的发病机制之一。

Objective To study the expression levels of plasma membranes Ca^2＋ -ATPase1b （PMCA1b） and Na^＋/Ca^2＋ exchanger 1 （NCX1 ） of Ca^2＋ active transport proteins on basolateral membrane in renal tubule epithelial cells of kidney tissue and their effect on idiopathic hypercalciuria formation. Methods Six male rats with genetic hypercalciuric stone-forming （GHS） and 6 male normal wild-type SD rats were enrolled. Real time quantitative PCR and Western blot were used to detect the protein and gene expression levels of PMCA1b and NCX1. Results NCX1 gene and protein levels had no significant change between GHS group and normal control （NC） group. PMCA1b gene levels had no significant change between GHS group and NC group. The average relative absorbance （A） value of PMCA1b in GHS group was significantly lower than that of the NC group [ （0.18 ± 0.05 ） and （0.43 ± 0.07 ） respectively] （ P 〈 0. 01 ）. Conclusion The low expression of PMCA1b protein may be one of the molecular mechanisms of idiopathic hypercalciuria formation.