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

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. Key words: Type 1 diabetes mellitus; Adiponectin; Receptor