Effects of triptergium glycosides on expressions of MCP-1 and CTGF in rats with early diabetic nephropathy

Abstract

Purpose: To investigate the effects of triptergium glycosides (TG) on expressions of monocyte chemoattractant protein-1 (MCP-1) and connective tissue growth factor (CTGF) in early diabetic nephropathy (DN) in rats, and explore its mechanism of renal protection. Methods: Thirty-two rats were divided into 4 groups: normal control (NC), DN, and DN-treated with TG (5 and 10 mg/kg/d) groups. After 8 weeks, body weight, blood glucose (BG), albumin (ALB), blood urea nitrogen (BUN), creatinine (SCr) and 24 h urinary total protein (UTP) of rats were determined. Additionally, expressions of CTGF, MCP-1 and ED-1 were detected by immunohistochemistry assay, while mRNA and protein expressions of CTGF and MCP-1 in kidney tissues were evaluated using reverse transcription-polymerase chain reaction (RT-PCR) and western blot technique. Results: BG, ALB, SCr, BUN and UTP in DN group were significantly increased (p < 0.01), compared with NC group. Compared with DN group, ALB (28.90 and 31.49 vs 23.13 g/L) and UTP (21.87 and 18.91 vs 37.19 mg/24 h) were significantly changed in TG groups (p < 0.05). ED-1 positive cells were significantly increased in DN group (p < 0.01), compared with NC group, whereas treatment with TG significantly reversed the increase (1.67 and 1.41 vs 2.73 in glomeruli, 9.86 and 9.49 VS 13.18 in glomerular interstitial, p < 0.01). Proteins and mRNA expressions of CTGF and MCP-1 significantly increased (p < 0.01) in DN group, compared with NC group, while their expressions in TG groups were reversed. Conclusion: TG ameliorates renal injury in diabetic rats via decreasing MCP-1 and CTGF expressions and reducing macrophage activation.