人类红细胞膜二氧化碳转运相关蛋白AQP-1和RhAG的研究

CO2 gas channel-related proteins in human red cell membrane

目的探讨人类红细胞膜上二氧化碳膜转运相关蛋白-水通道蛋白1(aquaporin-1,AQP-1)和RhAG蛋白(Rh-associated glycoprotein,RhAG)在不同二氧化碳浓度下表达量的变化。方法采集新鲜人血抗凝,离心制备红细胞悬液,采用免疫组织化学、流式细胞仪及Western blot法检测在二氧化碳浓度为5%、10%、15%、20%及25%时人类红细胞膜上AQP-1和RhAG的表达情况。结果 AQP-1和Rh蛋白随不同浓度二氧化碳表达量发生了很大变化,其中,AQP-1在二氧化碳浓度为20%时达到高峰,二氧化碳浓度为10%、15%、20%、25%与5%的AQP-1的表达量相比明显增强(P<0.05)。10%、15%、25%浓度之间AQP-1的表达量无显著性差异(P>0.05)。RhAG的表达量在二氧化碳浓度为10%时达到高峰,且10%、15%、20%、25%与5%的二氧化碳浓度下RhAG的表达量相比显著增强(P<0.05)。二氧化碳浓度为10%、15%、20%、25%RhAG之间浓度相比无显著性差异(P>0.05)。结论 AQP-1和RhAG表达量随不同二氧化碳浓度的变化而变化,表明两者在二氧化碳跨膜转运过程中,可能在不同二氧化碳浓度下发挥转运蛋白质的功能。

【Objective】 To study the protein expression level of CO2 gas channel-related proteins,aquaporin-1（AQP-1） and RhAG protein,under distinct CO2 concentration in human red cell membrane.【Methods】 Red blood cell suspension of fresh heparinized blood samples from healthy individuals was prepared via centrifugation.Flow cytometry was used to measure the protein expression level of AQP-1 and RhAG protein in red cell membrane under disparate CO2 concentration（5%,10%,15%,20% and 25%）,respectively.【Results】 We detected statistically significant differences in the protein expression level of both AQP-1 and RhAG protein in human red cell membrane with distinct CO2 concentration.Interestingly,AQP-1 protein showed its highest expression level with 20% CO2.Compared with its protein expression under 5% CO2,AQP-1 manifested significant higher expression level with 10%,15%,20% and 25% CO2 concentration,respectively,with no significant differences among these more concentrated conditions.While with 10% CO2 the protein expression level of RhAG protein reached its summit.Those more concentrated CO2 conditions（10%,15%,20%,25%） resulted in a significant higher Rh protein expression status than that with 5% CO2.Also significant differences in Rh protein expression were detected among these relatively higher CO2 conditions（10%,15%,20% and 25%）.【Conclusion】 Since the protein expression level of both AQP-1 and Rh protein varies significantly with diverse CO2 background,we conclude that AQP-1 and Rh protein may play pivotal roles and act as CO2 gas channels in human red cell membrane that allow passage of CO2,which,in turn,facilitates its transport.