Effects of hydrogen on expression of ROCK1 and mDia1 in intestinal tissues of septic mice

Abstract

Objective To evaluate the effects of hydrogen on the expression of Rho-associated protein kinase 1(ROCK1)and mammalian diaphanous-related formin 1(mDia1)in intestinal tissues of septic mice. Methods Ninety male C57BL/6 mice, weighing 20-25 g, aged 6 weeks, were divided into 3 groups(n=30 each)using a random number table: control group(group C), sepsis group(group S)and sepsis plus hydrogen group(group SH). Sepsis was produced by cecal ligation and puncture(CLP). Group SH inhaled 2% hydrogen for 1 h starting from 1 and 6 h after CLP.Twenty mice in each group were selected and observed for 7-day survival rate.Ten mice in each group were sacrificed at 24 h after CLP, and blood samples were obtained from hearts to measure the activity of serum diamine oxidase(DAO)and to count the colony-forming units after bacterial culture.The small intestinal samples were obtained for microscopic examination of pathological changes and for determination of ROCK1 and mDia1 positive cell rates(using immunohistochemical staining)and expression of intestinal epithelial junctional protein E-cadherin(by immunofluorescent staining). Intestinal damage was assessed and scored.The ratio of ROCK1 to mDia1 positive cell rates(ROCK1/mDia1 ratio)was calculated. Results Compared with group C, the survival rate was significantly decreased, the serum DAO activity, colony counts and intestinal damage scores were increased, ROCK1 and mDia1 positive cell rates were increased, and the expression of E-cadherin was down-regulated in S and SH groups, ROCK1/mDia1 ratio was increased in group S(P 0.05). Compared with group S, the survival rate was significantly increased, the serum DAO activity, colony counts and intestinal damage scores were decreased, the ROCK1 positive cell rate was decreased, the mDia1 positive cell rate was increased, ROCK1/mDia1 ratio was decreased, and the expression of E-cadherin was up-regulated in group SH(P<0.05). Conclusion The mechanism by which hydrogen improves intestinal barrier function may be related to down-regulation of ROCK1 expression, up-regulation of mDia1 expression and correction of the imbalance in ROCK1/mDia1 ratio in intestinal tissues of septic mice. Key words: Hydrogen; Sepsis; rho-associated kinases; rhoA GTP-binding protein; Intestinal mucosa