Protective effect of adiponectin and its receptors in diabetic nephropathy rats / 中华肾脏病杂志

ABSTRACT

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.