脂联素及其受体对糖尿病肾病大鼠的保护作用

Protective effect of adiponectin and its receptors in diabetic nephropathy rats

目的 探讨脂联素（ADPN）及其受体（AdipoR）对糖尿病肾病的保护作用及其可能机制.方法 （1）64只雌性SD大鼠被随机均分入对照组和实验组：实验组一次性空腹腹腔注射链脲菌素（STZ）60 mg/kg,诱导糖尿病大鼠模型;对照组腹腔注射等体积的枸橼酸缓冲液.于糖尿病大鼠成模后第2、6、10、12周两组分别测体质量、肾质量、空腹血糖、24 h尿白蛋白排泄量;心内采血检测空腹血清胰岛素;ELISA法检测血、尿脂联素浓度;取肾脏常规制作PAS染色,免疫组化SP法检测肾脏脂联素受体1和2（AdipoR1和AdipoR2）的表达.（2）将NRK-52E细胞分别用含5 mmol/L葡萄糖（正常对照组）、30 mmol/L葡葡糖（高糖组）、30mmol/L葡萄糖＋不同浓度ADPN（终浓度分别为1 mg/L、5 mg/L、10 mg/L）培养,12 h后RT-PCR法检测单核细胞趋化蛋白1（MCP-1）mRNA表达.结果 （1）造模成功后6、10、12周实验组血清和尿ADPN水平均高于对照组（P＜0.01）,并随着肾脏病变进展而逐渐升高.（2）实验组各时期AdipoR1和AdipoR2在肾脏的表达高于对照组,并随时间逐渐增强,其与血清脂联素水平呈正相关（r=0.666,P＜0.01;r=0.684,P＜0.01）.（3）MCP-1 mRNA在高糖组表达较高,加入脂联素以后MCP-1 mRNA表达显著减少（P＜0.05）.结论 血和尿脂联素水平随糖尿病肾病病程进展而升高,与AdipoR1和AdipoR2的表达亦呈正相关,推测脂联素通过AdipoR直接作用于肾小管,通过减少MCP-1的表达对肾脏起保护作用.

Objective To investigate the protective effect and possible mechanism of adiponectin （ADPN） and its receptors in diabetic nephropathy （DN）. Methods A total of 64 Sprague-Dawley female rats were equally divided into diabetes mellitus （DM） group with streptozotocin（STZ） 60 mg/kg injection, and normal control （NC） group with the same dose of citric acid buffer randomly. At the end of 2, 6, 10 and 12 weeks, weight, fast blood glucose, 24-hour urinary albumin excretion, serum creatinine and serum fast blood insulin were measured. The level of adiponectin in urine and serum was examined by ELISA. The pathological change of kidney tissue was studied by periodic acid-Schiff＇s staining （PAS） and the expression of adiponectin receptor 1 （adipoR1）, adiponectin receptor 2 （adipoR2） was determined by immunohistochemistry.The NRK-52E cells were cultured with 5 mmol/L glucose （control group）, 30 mmol/L glucose （high glucose group）, 30 mmol/L glucose＋different concentrations of adiponectin （1 mg/L, 5 mg/L, 10 mg/L, ADPN groups）, respectively. The mRNA expression of monocyte chemoattractant protein 1 （MCP-1） was measured by RT-PCR after 12 h. Results （1）Both in urine and serum, the levels of ADPN in DM group were higher than that in NC group after 6 weeks （P〈0.01） and increased gradually during the whole experiment. （2）Compared with NC group, the expressions of AdipoR1 and AdipoR2 in kidney tissues were elevated gradually in DM group. There was a significant positive correlation of ADPN with AdipoR1 and AdipoR2 in DM group（r=0.666, P〈0.01;r= 0.684, P〈0.01）. （3）The expression of MCP-1 increased in high glucose group, but decreased in 1 mg/L, 5 mg/L, 10 mg/L adiponectin group. Conclusions The level of ADPN in urine and serum is positively correlated with its receptors and elevates with the process of diabetic kidney disease. High level of serum adiponectin plays a protective role through the direct action of AdipoR and the alleviation of MCP-1 expression in renal tubules.