nephrin、血管内皮生长因子及其受体表达与先兆子痫大鼠蛋白尿的关系

Association of the expressions of glomerular nephrin, vascular endothelial growth factor and its receptor with proteinuria in preeclampsia rats

目的 研究nephrin、血管内皮生长因子（VEGF）及其受体（VEGFR）在先兆子痫大鼠肾组织的表达与蛋白尿的关系.方法 采用一氧化氮合酶抑制剂（L-NAME）制备大鼠先兆子痫模型（n=8）,分别与正常雌性组（n=6）、正常妊娠组（n=8）、未孕L-NAME对照组（n=6）大鼠比较动脉收缩压（SBP）、尿蛋白量（24 h）.各组大鼠肾组织分别行光镜和电镜检查.Western印迹法、实时定量PCR检测nephrin在各组大鼠肾脏局部的表达;免疫荧光法检测各组大鼠肾小球内wilms肿瘤蛋白WT1的表达.Western印迹法检测VEGF及VEGFR（Flt-l、Flk-1）在各组大鼠肾脏局部的表达.结果 先兆子痫模型组大鼠nephrin蛋白的表达（0.0726±0.0074）显著低于正常雌性组（0.3795±0.0509）、正常妊娠组（0.2361±0.0437）及未孕L-NAME对照组大鼠（0.7265＋0.0503）（均P＜0.01）;而nephrin mRNA在各组大鼠间差异无统计学意义.各组大鼠足细胞数目差异无统计学意义.先兆子痫大鼠组VEGF的表达（1.5429±0.0898）显著高于正常雌性组（1.1870±0.1160）、正常妊娠组（1.3741±0.1165）、未孕L-NAME对照组大鼠（1.0155±0.0742）（均P＜0.01）;先兆子痫组大鼠VEGFR（Flt-1、Flk-1）的表达均显著高于其他各对照组大鼠（均P＜0.05）.结论 先兆子痫大鼠中,nephrin蛋白水平表达明显降低,肾脏局部VEGF-VEGFR表达显著增强,可能参与了先兆子痫蛋白尿的生成,其具体机制有待进一步研究.

Objective To investigate the association of the expressions of glomerular nephrin, vascular endothelial growth factor （VEGF） and its receptor （VEGFR） with proteinuria in preeclampsia rats. Methods A rat model of preeclampsia was developed by inhibitor of nitric oxide synthase （L-NAME）. The systolic blood pressure （SBP） and 24 h urine protein were compared among the normal female group （n=6）, the normal pregnant group （n=8）, nonpregnant control group （n=6） and preeclampsia group（n=8）. The kidney biopsies of each group were observed by light and electron microscopy. The glomerular nephrin was detected by Western blotting and real-time PCR. Immunofluorescence was used to detect the expression of WT1. The level of glomerular VEGF and VEGFR （Flt-1 and Flk-1） were evaluated by Western blotting. Results The level of glomerular nephrin protein in the rats with preeclampsia （0.0726±0.0074） was significantly lower compared with normal female group （0.3795±0.0509）, normal pregnant group （0.2361±0.0437） and nonpregnant control group （0.7265±0.0503） （P〈0.01, respectively）, while the levels of nephrin mRNA were not significantly different among 4 groups. The expression of WT1 was not significantly different among 4 groups as well. The level of glomerular VEGF in preeclampsia group （1.5429±0.0898） was significantly higher compared with normal female group （1.1870±0.1160）, normal pregnant group （1.3741 ±0.1165） and nonpregnant control group （1.0155±0.0742）（P〈0.01,respectively）. VEGFR （Flt-1 and Flk-1） was also significantly higher in preeclampsia rats compared with other control groups （P〈0.05, respectively）. Conclusions In preeclampsia rats, nephrin is decreased significantly and the glomerular VEGF-VEGFR is increased significantly compared with the other control groups. The abnormal expression of nephrin and VEGF-VEGFR may be involved in the preeclampsia proteinuria. The underlying mechanism of this phenomenon needs further research.