High glucose induced inflammatory response and fibrosis of human mesangial cells via Rho/ROCK signaling pathway

Abstract

Objective To investigate the role of Rho/ROCK signaling pathway in the process of human mesangial cells (HMCs) inflammation and fibrosis induced by high glucose. Methods Synchronized HMCs were divided into following groups: ( 1 ) Normal glucose control group ( NG, 5.5 mmol/L glucose); ( 2 ) High glucose group ( HG, 30 mmol/L glucose); (3) Mannitol group( Man,5.5 mmol/L glucose+ 24.5 mmol/L mannitol); (4) NG +Y-27632 group( 10 μ mmol/L Y-27632 ); ( 5 ) HG Y-27632 group ( 10 μmmol/L Y-27632 ). The supernatant and cells were collected at 0,12,24,36,48, and 72 h. Western blot was used to detect the active RhoA and total RhoA,while RhoA, ROCK-Ⅰ, CTGF, and TNF-α mRNA expressions were determined with realtime PGR method in the cells, then ELISA method was used to check protein levels of FN, CTGF, and TNF-α in the supernatant. Results ( 1 ) RhoA activation was stimulated after treatment for with 30 mmol/L glucose, peaked at 1 h, and then decreased ( P = 0. 02). (2) RhoA, ROCK-Ⅰ, CTGF, and TNF-α mRNA expressions in HMC cultured under high glucose were higher than those in the normal group ( P ＜ 0.05 ), and there was certain time-dependence. Besides, there was no statistical significance between Man and NG groups( P＞0. 05 ). ( 3 ) After Y-27632 pretreatment and being cultured with normal glucose and high glucose for24 h or48 h, RhoA, ROCK-Ⅰ, CTGF, and TNF-α mRNA expressions were significantly decreased ( P＜0.01 ) as compared with groups without treatment. (4) High glucose increased FN, CTGF,and TNF-α protein secretion of HMC in a time-dependent manner( P＜0. 05 ). ( 5 ) After Y-27632 pretreatment and being cultured with normal and high glucose for 12,24,36,48,72 h, FN, CTGF, and TNF-α protein secretions were significantly reduced( P＜0.05 ). Conclusion Rho/ROCK signaling pathway may mediate inflammation and fibrosis induced by high glucose in HMCs, supporting a potential role for inhibitors of Rho/ROCK in the treatment of diabetic nephropathy. Key words: Human mesangial cells; Rho/ROCK signaling pathway; High glucose; Inflammatory response; Fibrosis