链脲佐菌素诱导的1型糖尿病大鼠肾脏脂联素受体的表达

Renal adiponectin receptor expression in STZ-induced type 1 diabetic rats

目的 观察链脲佐菌素(STZ)诱导的糖尿病大鼠在不同时期其血清脂联素和脂联素受体(AdipoR)在肾脏组织的表达水平.方法 64只雌性SD大鼠按随机数字表法分为对照组和实验组(分别为2、6、10、12周,共8组):实验组大鼠32只,一次性空腹腹腔注射STZ 60 mg/kg,诱导糖尿病大鼠模型;对照组大鼠32只,腹腔注射等体积的枸橼酸缓冲液.分别于糖尿病大鼠成模后第2、6、10、12周两组各取8只,测体重、肾重、空腹血糖、24 h尿白蛋白定量;心内采血,离心取血清,检测血肌酐,空腹血清胰岛素;ELISA方法检测血、尿脂联素浓度.取左肾常规病理组织行糖原染色,在光镜下观察肾脏的病理组织学改变,免疫组化SP法检测肾脏2种受体AdipoR1和AdipoR2表达.结果 (1)实验组6、10、12周大鼠血清和尿脂联素高于对照组,差异有统计学意义(P＜0.01);且血清脂联素与24 h尿白蛋白排泄率、尿脂联素呈正相关(r值分别为0.806、0.696,均P＜0.01);尿脂联素与24 h尿白蛋白定量呈显著正相关(r=0.728,P＜0.01);逐步回归分析提示血清脂联素受24 h尿白蛋白定量影响最大(β=0.806,P＜0.01);(2)免疫组化半定量分析显示,AdipoR1和AdipoR2在正常大鼠肾组织中均有表达,主要分布于肾小管上皮细胞和肾小球内皮细胞.实验组造模成功6周时肾脏组织AdipoR1和AdipoR2表达,与对照组比较表达有所增强(F值分别为11.68、23.20,均P＜0.01),且与血清脂联素呈显著正相关(r值分别为0.666、0.684,均P＜0.01).结论 血清和尿脂联素水平与糖尿病肾病病程和AdipoR呈正相关,推测脂联素通过AdipoR直接作用于肾脏,尤其是作用于肾小管,在1型糖尿病肾脏病变中发挥保护作用.

Objective To explore the role of adiponectin and receptors of adiponectin ( AdipoR1,AdipoR2) in the development of diabetic kidney disease (DKD) in diabetes mellitus rats induced by streptozotocin (STZ). Methods A total of 64 SD rats were randomly divided into two groups. Thirty-two rats were in normal control(NC) group and the others were in diabetes mellitus(DM) group. The rats in DM group were injected STZ intraperitoneally with a dose of 60 mg/kg while the ones in NC group were only done with the same dose of citric acid buffer. At 2,6,10 and 12 weeks, weight,fast blood glucose and 24-hour urinary albumin excretion were recorded, serum fast blood insulin was also measured. Adiponectin levels in urine and serum were evaluated by ELISA. The pathological changes of kidney were examined by light microscope. Renal expression of AdipoR1, AdipoR2 was determined by immunohistochemistry. Results ( 1 ) The levels of adiponectin in urine and blood in DM group were higher than that in NC group after 2 weeks(6 weeks, 10 weeks, 12 weeks, P ＜0. 01 ) and increased gradually during the whole experiment.Correlative analyses revealed a positive correlation between serum adiponectin and the quantification of albumin in 24 h urine, urinary adiponectin ( r = 0. 806, P ＜ 0. 01; r = 0. 696, P ＜ 0.01 ) and between urinary adiponectin and the quantification of albumin in 24 h urine ( r = 0. 728, P ＜ 0.01 ). Stepwise regression analyses showed that the quantification of albumin in 24 h urine was independently associated with adiponectin concentrations( β =0. 806, P ＜0.01 ). (2) Compared the NC group,the expressions of AdipoR1 and AdipoR2 in kidney tissue were enhanced in DM group, and increased gradually (F value was 11.68,23. 20,respectively). There was a significant positive correlation between adiponectin and AdipoR1 and AdipoR2 in DM group(r =0.666, P＜0.001; r=0.684, P＜0.01). Conclusion With the progression of DM, the levers of adiponectin and its receptors increase which shows a significant protective effect in renal damage.