Study on mechanism of IL-1β mediating vascular calcium desensitization in septic rats through down-regulating Rho kinase activity / 重庆医学

ABSTRACT

Objective To investigate the mechanism of interleukin-1β(IL-1β) mediating the vascular calcium desensitization of septic rats by down-regulating Rho kinase activity.Methods Thirty-two SD rats were randomly divided into the sham operation group,cecal ligation and puncture (CLP) 3 h group,CLP 6 h group and CLP 12 h group,8 cases in each group.The septic rat was duplicated by CLP.Then the plasma IL-1β level and calcium sensitivity of superior mesenteric arteries (SMAs) were detected at different time points.Their correlation was analyzed.VSMCc derived from SMAs were cultured and incubated with different concentrations of human recombinant IL-1β for 24 h.Then the influences of IL-1β on the MLC20 phosphorylation level,Rho kinase activity,G protein expression level and RhoGEF activity were observed.Results The calcium sensitivity of SMAs after CLP 3 h began to decrease(P＜0.05),while plasma IL-1β level began to increase after CLP 6 h (P＜0.05),the change trend of SMAs calcium sensitivity was negatively correlated with plasma IL-1β level change(P＜0.05).IL-1β could decrease the phosphorylation level of VSMCs myosin light chain(MLC20) and Rho kinase activity(P＜0.05),up-regulate Gα11 expression and down-regulate Gα12 expression,but had no obvious effect on Gαq and Gα13 expression(P＞0.05).IL-1β could significantly reduce RhoGEF and PDZ-RhoGEF activity(P＜0.05) but significantly increase p63 Rho GEF activity(P＜0.05).Conclusion IL-1β induces the decrease of PDZ-RhoGEF and Rho kinase activity by down-regulating Gα12 expression,causes the decrease of MLC20 phosphorylation level,thus mediates the occurrence of calcium desensitization in septic rat;in addition,IL-1β may cause the increase of p63 RhoGEF activity by upregulating Gα11 expression,thus mediates the increase of vascular calcium sensitivity in septic rats,but the total effect is the decrease of calcium sensitivity.