Fang Wei, Qian Jiaqi, Yu Zhiyuan, Chen Shishu
Renal Division, Renji Hospital, Shanghai Second Medical University, Shanghai 200001, China.
Chin Med J (Engl). 2003 Sep;116(9):1370-3.
To investigate the expression of aquaporin-1 (AQP1) in the human peritoneum and to evaluate the effect of peritoneal dialysis (PD) on its expression.
Peritoneal biopsies were obtained from normal subjects (n = 10), uremic nondialysis patients (n = 12) at catheter insertion and PD patients (n = 10) at the time of catheter removal, reinsertion or renal transplantation. Western blot, immuno-histochemical staining and reverse transcript-polymerase chain reaction (RT-PCR) techniques were used to investigate AQP1 expression.
All peritoneal samples expressed AQP1 at both mRNA and protein levels. Western blot revealed a major band at 28 kD as well as more diffuse bands between 35 and 50 kD. The 28 kD band represents the nonglycosylated form of the protein while the 35 - 50 kD bands correspond to glycosylated AQP1. Immunohistochemical staining found the positive deposits were distributed in the mesothelial cells, endothelial cells of capillaries, venules and small veins, whereas no signal was detected in the arterioles. Semi-quantitative analysis showed that AQP1 expression was remarkably stable in all samples, whatever their origin (P > 0.05).
Our findings suggested that AQP1 is the molecular counterpart of an ultra small pore during PD. Secondly, the peritoneal mesothelial cell might also be involved in peritoneal transcellular water transport. As regards whether or not the structural or distributional alterations of AQP1 in the peritoneum may be more obviously expressed during PD, further study is needed.
研究水通道蛋白-1（AQP1）在人腹膜中的表达，并评估腹膜透析（PD）对其表达的影响。
从正常受试者（n = 10）、尿毒症未透析患者（n = 12，在插入导管时取材）以及PD患者（n = 10，在拔除导管、重新插入导管或肾移植时取材）获取腹膜活检组织。采用蛋白质免疫印迹法、免疫组织化学染色法及逆转录-聚合酶链反应（RT-PCR）技术研究AQP1的表达。
所有腹膜样本在mRNA和蛋白质水平均表达AQP1。蛋白质免疫印迹法显示，在28 kD处有一条主要条带，在35至50 kD之间还有更多弥散条带。28 kD条带代表该蛋白的非糖基化形式，而35至50 kD条带对应糖基化的AQP1。免疫组织化学染色发现，阳性沉积物分布于间皮细胞、毛细血管内皮细胞、小静脉和小静脉中，而在小动脉中未检测到信号。半定量分析表明，无论样本来源如何，AQP1的表达在所有样本中均非常稳定（P > 0.05）。
我们的研究结果表明，AQP1是PD过程中一个超小孔的分子对应物。其次，腹膜间皮细胞也可能参与腹膜跨细胞水转运。至于PD过程中腹膜中AQP1的结构或分布改变是否会更明显地表现出来，还需要进一步研究。
