血管内皮生长因子在大鼠慢性移植肾肾病早期病变中的作用及机制

Role of vascular endothelial growth factor in rats with chronic allograft nephropathy at early stage

目的探讨血管内皮生长因子（VEGF）在慢性移植肾肾病（CAN）早期病变中的作用及其机理。方法依照标准的大鼠CAN模型进行大鼠左肾原位肾移植，供鼠为F344大鼠，受鼠为Lewis大鼠，术后10d切除受鼠自体右肾。供、受鼠对照组分别为单纯右肾切除的F344大鼠和Lewis大鼠。分别于术后4、8和12周时，获取各组大鼠的尿液、外周血和肾组织样本，检测24h尿蛋白、尿肌酐及血肌酐水平，采用免疫组织化学法检测肾组织中VEGF和整合素连接酶（ILK）的表达水平。结果移植组大鼠在术后4周时肾间质可见单个核细胞浸润，12周时可见血管平滑肌细胞的移行与增殖，移植组各时点ILK和VEGF表达水平显著高于同时点的供、受鼠对照组（P〈0．05），移植组大鼠VEGF表达水平与24h尿蛋白定量、血清肌酐水平、肾间质单个核细胞浸润、肾小动脉血管平滑肌细胞数量呈显著正相关，相关系数（r）分别为0．713（P〈0．05）、0．534（P〈0．01）、0．845（P〈0．01）、0．539（P〈0．01）、0．506（P〈0．01）。肾小管间质及肾小动脉中VEGF与ILK表达水平呈显著正相关（r=0．446，P〈0．01）。结论VEGF表达上调在大鼠CAN早期病理变化中起到重要作用，移植肾肾小管间质及肾小动脉中VGEF表达上调与ILK的作用机制相关。

Objective To investigate the role of vascular endothelial growth factor （VEGF） in rats with chronic allograft nephropathy （CAN） at early stage. Method The left donor kidneys from Fisher（F344） rats were orthotopically transplanted into Lewis（LEW） recipients. Meanwhile, the F344 rats and LEW rats subject to right nephrectomy served as control groups. The urine, peripheral blood and renal tissues were harvested respectively at the 4th, 8th, and 12th week after transplantation. The creatinine clearance rate （CCr） was calculated by urine creatinine of 24 h urine. The level of 24 h urine protein was determined. The serum creatinine level was measured. The expression of VEGF and integrin-linked kinase （ILK） was detected by using immunohistochemistry. Results Infiltration of mononuclear cells in allografts was markedly aggravated as compared with the controls at the 4th week after transplantation. Allografts got severe interstitial fibrosis and tubular atrophy at the 12 th week after transplantation. The expression of VEGF and ILK was up-regulated in the kidney of CAN rats after transplantation as the time went on. The expression of VEGF was significantly correlated with 24 h urine protein excretion （r = 0. 713, P〈0. 05）, serum creatinine levels （r = 0. 534, P〈0. 01 ）, the number of tubulointerstitial infiltrated mononuclear cells （r = 0. 845,P〈0. 01）, the number of smooth muscle cells in vascular wall （r= 0. 539,P〈0. 01）, and the extent of interstitial fibrosis （r= 0. 506, P 〈0. 01）. There was a significantly positive correlation between VEGF and ILK in CAN rats after transplantation （r = 0. 446, P〈0. 01 ）. Conclusion VEGF might play an key role in CAN at early stage, and the up-regulated VEGF in the tubulointerstitium and vascular wall is correlated with the role of ILK in the CAN.