Renal expression of RANK- RANKL in a rat model of puromycin aminonucleoside nephropathy

目的：探讨RANK-RANKL在嘌呤霉素氨基核苷肾病（PAN）大鼠动物模型肾脏中的表达。方法36只SD大鼠被分配为PAN组及对照组，单次静脉注射嘌呤霉素氨基核苷（PA，100 mg/kg）制作PAN动物模型。大鼠于第3、7、14天检测蛋白尿及血肌酐。检测肾脏病理，并分析RANK和RANKL变化。结果（1）在PAN SD大鼠动物模型中，第3、7、14天时蛋白尿与对照组比较有显著差别，第7天达到高峰；（2）用Western blotting及RT-PCR定量检测发现RANK-RANKL蛋白及mRNA在PAN模型组高于对照组；（3）用激光共聚焦技术显示足细胞标记蛋白Synaptopodin与RANK完全重合，提示RANK主要在足细胞表达；（4）免疫电镜发现RANK在PAN模型组明显增多，且主要定位于足突的顶部胞膜和胞质内。结论在PAN SD大鼠动物模型足细胞异常表达RANK-RANKL，提示RANK及RANKL在足细胞损伤中可能发挥重要作用。Objective To investigate RANK-RANKL expression in the kidneys of a rat model of puromycin aminonucleoside nephropathy (PAN). Methods Thirty-six SD rats were randomly divided into PAN model group and normal control group. PAN was induced by a single intravenous injection of 100 mg/kg puromycin aminonucleoside. Serum creatinine and 24-hour urinary protein were measured on days 3, 7, and 14 after the injection, and renal pathologies were assessed with optical and immune transmission electron microscopy. The expression of RANK and RANKL in the kidneys was examined using reverse transcription-ploymerase chain reaction (RT-PCR) and Western blotting. Results The PAN model rats showed massive proteinuria and elevated serum creatinine on day 3, which peaked on day 7. RANK-RANKL protein and mRNA expressions in PAN model group was higher than those in the control group. In the PAN rats, RANK was expressed mainly on the top cell membrane and in the cytoplasm of renal podocytes with a significantly increased expression level compared with that in the control group. Conclusion The PAN rat model shows aberrant RANK and RANKL expressions in the podocytes, indicating their contribution to podocyte injury in PAN.广东省自然科学基金(8151008004000022)；广东省科技计划项目(2011B031800303；2012B03180016)；广州市科技计划科技攻关项目中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)0165-6