磷酸化肌球蛋白轻链在大鼠慢性移植肾肾病早期病变中的作用及其机制

目的 探讨磷酸化肌球蛋白轻链(pMLC)在慢性移植肾肾病(CAN)中的作用与机制.方法 依照标准的CAN大鼠模型进行左肾原位移植,受者为LEW大鼠,供者为F344大鼠,另取雄性F344大鼠和LEW大鼠仅行单肾切除术,分别作为对照.分别于术后4、8及12周时,收集各组大鼠的24 h尿量,并检测其尿肌酐水平,计算肌酐清除率.然后取各组大鼠血液标本,测定血清肌酐水平.采用Banff分级标准评定各组肾小球肾病、肾小管萎缩、间质纤维化及血管内膜增厚程度.采用免疫组织化学法和采用蛋白质印迹法检测肾组织中磷酸化MLC(pMLC)和整合素连接激酶(ILK)的表达部位及表达水平.结果 移植组大鼠术后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.移植组大鼠各时相肾组织pMLC和ILK表达水平显著高于Lewis对照组及F344对照组,且随着移植时间的延长有逐渐增高趋势.大鼠移植肾组织中pMLC表达水平与24 h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、Banff评分等呈显著正相关,相关系数(r)分别为0.273(P＜0.05)、0.434(P＜0.01)、0.525(P＜0.01)、0.676(P＜0.01)、0.570(P＜0.01),在移植后4周时,pMLC表达水平与肾小管间质ILK表达水平呈显著正相关,r=0.778(P＜0.01).结论 pMLC在慢性移植肾病早期病理变化中发挥重要作用,移植肾肾小管间质及肾小动脉中pMLC表达上调与ILK的作用机制相关.

Abstract：

Objective To investigate the role and mechanism of phosphate myosin light chain (pMLC) in the rat kidney of chronic allograft nephropathy (CAN) model. Methods The left donor kidneys from Fisher (F344) rats were orthotopically transplanted into Lewis recipients. Meanwhile, the F344 rats and LEW rats with resection of the right kidney served as control groups. Animals 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. Blood samples were collected from rats for determination of serum creatinine. The expression of pMLC was detected by using Western blotting and immunohistochernistry, and that of integrin-linked kinase (ILK) by using immunohistochemistry. Results Mononuclear cells infiltration of allografts was markedly aggravated as compared to the controls. Allografts got severe interstitial fibrosis and tubular atrophy at 12th week after transplantation. The expression of pMILC and ILK was up-regulated in the kidney of CAN rats after transplantation, and increased more significantly as the time went on. The expression of pMILC was significantly correlated with 24-h urine protein excretion (r= 0. 273, P＜0. 05), serum creatinine levels (r = 0. 434, P＜0. 01 ), the number of tubulointerstitial infiltrated mononuclear cells (r = 0. 525, P＜0. 01 ), the number of smooth muscle cells (SMC) in vascular wall (r= 0. 676, P＜0. 01 ) and the extent of interstitial fibrosis (r= 0. 570, P＜0. 01 ).There was a significantly positive correlation between ILK and pMLC in CAN rats at the 4th week after transplantation (r= 0. 778, P＜0. 01 ). Conclusion pMLC might play an key role in CAN, and the over-expression of ILK might be involve in the pathogenesis of CAN.

Role and mechanism of phosphate myosin light chain in chronic allograft nephropathy of rats

Objective To investigate the role and mechanism of phosphate myosin light chain (pMLC) in the rat kidney of chronic allograft nephropathy (CAN) model. Methods The left donor kidneys from Fisher (F344) rats were orthotopically transplanted into Lewis recipients. Meanwhile, the F344 rats and LEW rats with resection of the right kidney served as control groups. Animals 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. Blood samples were collected from rats for determination of serum creatinine. The expression of pMLC was detected by using Western blotting and immunohistochernistry, and that of integrin-linked kinase (ILK) by using immunohistochemistry. Results Mononuclear cells infiltration of allografts was markedly aggravated as compared to the controls. Allografts got severe interstitial fibrosis and tubular atrophy at 12th week after transplantation. The expression of pMILC and ILK was up-regulated in the kidney of CAN rats after transplantation, and increased more significantly as the time went on. The expression of pMILC was significantly correlated with 24-h urine protein excretion (r= 0. 273, P＜0. 05), serum creatinine levels (r = 0. 434, P＜0. 01 ), the number of tubulointerstitial infiltrated mononuclear cells (r = 0. 525, P＜0. 01 ), the number of smooth muscle cells (SMC) in vascular wall (r= 0. 676, P＜0. 01 ) and the extent of interstitial fibrosis (r= 0. 570, P＜0. 01 ).There was a significantly positive correlation between ILK and pMLC in CAN rats at the 4th week after transplantation (r= 0. 778, P＜0. 01 ). Conclusion pMLC might play an key role in CAN, and the over-expression of ILK might be involve in the pathogenesis of CAN.