“两肾一夹”高血压大鼠肾组织中足细胞蛋白podocalyxin的表达及与氧化应激的关系

目的探讨足细胞顶端膜蛋白podocalyxin（PCX）在“两肾一夹”高血压大鼠肾组织中的表达及其与氧化应激的关系。方法将30只雄性SD大鼠随机分为实验组（n=20）和对照组（n=10），对实验组大鼠以改进的“两肾一夹”方法建立高血压大鼠模型。分别于造模前和造模后1、5、10周检测2组尿胆微球蛋白（β-MG）、血肌酐和尿素氮水平；黄嘌呤氧化酶法测定超氧化物歧化酶（SOD）活力，酶联免疫吸附法（ELISA）测定8-异前列腺素F2α（8-iso-PGF2α）含量；免疫荧光方法观察PCX蛋白在肾组织的表达；PAS染色观察肾脏病理改变。结果实验组尿β2-MG自术后一直呈上升趋势，至术后5周时尿β-MG已明显高于对照组（P〈0．01），并且随着高血压病情的延续而进行性增加。2组血肌酐和尿素氮在整个实验过程中无明显差异（P〉0．05）。实验组8-iso-PGF2α含量高于对照组（P〈0．01），SOD活性低于对照组（P〈0．01）。免疫荧光可见实验组PCX表达低于对照组（P〈0．01），且实验组PCX表达量与8-iso-PGF2α含量呈负相关（r=-0．584，P〈0．05），与SOD活性呈正相关（r=0．656，P〈0．05）。结论氧化应激可以损伤PCX蛋白，进而使其表达降低，导致肾小球电荷屏障受损，尿蛋白排泄增加，在高血压。肾损害的早期发挥作用。

Expression of podocalyxin in renal tissue of 2-kidney-1-clip hypertensive rats and its relationship with oxidative stress

Objective To investigate the expression of podocalyxin （PCX） in the renal tissue of 2-kidney-l-clip hypertensive rats and its relationship with oxidative stress. Methods Thirty male SD rats were randomly assigned into two groups： experimental group （n = 20） and control group （n = 10）. Improved 2-kidney-l-clip hypertensive models in rats were used in the experiment. The urinary ]32-microglobulin （β2-MG）, serum creatinine （SCr） and blood urea nitrogen （BUN） were monitored at different stages. The activity of SOD was measured by using xanthine oxidase method, and the content of 8-iso PGF2α was determined by ELISA. The expression of PCX in the renal tissues was detected by using immunofluorescence. The pathological changes of the kidney were observed through PAS dye- ing. Results The urinary 132-MG in experimental group was significantly higher than in control group （P〈0. 01）. There was an increasing incidence of the urinary β2-MG after operation, and at the 5th week, urinary β2 MG in experimental group was significantly higher than in control group （P〈0. 01 ）. But there was no significant difference in SCr and BUN levels between experimental group and control group in the whole process （P〉0. 05）. The 8-iso-PGF2α in experimental group was higher than in control group （P〈0. 01）, but SOD activity was lower （P〈0. 01）. The expression of PCX in experimental group was significantly lower than in control group （P〈0. 01）, and it was negatively correlated with 8-iso-PGFEα （r= - 0. 584, P〈0. 05） and positively with SOD （r= 0. 656, P〈0. 05）. Conclusions Oxidative stress can damage PCX, lead to injury of charge barrier in glomerulus, and play an important role in early hypertensive renal disease.