Rho激酶调节缺氧处理VSMC收缩反应性与MLC20磷酸化的关系  

Role of MLC_(20) phosphorylation in the regulation Rho-kinase on the contractile response of VSMC to NE following hypoxia

作　　者：李涛[1] 刘良明[1] 刘建仓[1] 

机构地区：[1]解放军第三军医大学大坪医院野战外科研究所二室创伤、烧伤与复合伤国家重点实验室,重庆400042

出　　处：《中国急救医学》2008年第1期34-38,共5页Chinese Journal of Critical Care Medicine

基　　金：国家自然科学基金资助项目(No.30370563,30600228,30625037);国家973计划项目(No.2005CB522601)

摘　　要：目的观察Rho激酶调节缺氧处理的VSMC收缩反应性与MLC20磷酸化的关系。方法取肠系膜动脉VSMC,观察缺氧不同时间VSMC收缩反应性变化及Rho激酶活性调节剂对VSMC收缩反应性的影响。同时观察Rho激酶的激动剂和抑制剂对缺氧VSMCMLC20磷酸化水平以及MLCP和MLCK活性的影响。结果缺氧后,VSMC收缩反应性发生明显变化,缺氧10min时VSMC收缩反应性有所升高,缺氧60、90以及120min后,VSMC收缩反应性明显降低。Rho激酶激动剂Ang-Ⅱ(10-9mol/L)可升高缺氧90minVSMC收缩反应性,Y-27632拮抗Ang-Ⅱ的作用增强。缺氧后VSMCMLC20磷酸化水平明显降低,MLCP活性明显升高,MLCK活性明显降低,Rho激酶激动剂Ang-Ⅱ(10-9mol/L)可使缺氧引起的降低的MLC20磷酸化水平升高,使增高的MLCP活性降低,Y-27632(10-5mol/L)可拮抗Ang-Ⅱ的这一作用。Ang-Ⅱ和Y-27632对缺氧后VSMCMLCK活性无明显影响。结论MLC20磷酸化在Rho激酶调节缺氧VSMC收缩反应性变化中具有重要作用,Rho激酶可通过调节MLCP的活性来调节休克MLC20磷酸化水平,MLCK在Rho激酶调节休克MLC20磷酸化中无明显作用。Objective To observe the role of 20 kDa myosin light chain（MLC20）phosphorylation in Rho-kinase regulating contractile response of vascular smooth muscle cell（VSMC）following hypoxia.Methods With transwell culture,the contractile response of VSMC to NE at different time after hypoxia（10,30,60,90,120 min after shock）and the effects of Ang-Ⅱ and Y-27632 were observed.The phosphorylation of MLC20,activity of myosin light chain phosphatase（MLCP）and the myosin light chain kinase（MLCK）of VSMC and the effects of Ang-Ⅱ,Y-27632（the Rho-kinase activity regulating agents）on the activity of MLCP,MLCK and the phosphorylation of MLC20 were also observed.Results The contractile response of VSMC to NE was increased at 10 min after hypoxia,but it was decreased at 60 min,90 min and 120 min after hypoxia（P〈0.05 or P〈0.01）.Ang-Ⅱ（10^-9mol/L）increased the contractile response of VSMC to NE at 90 min after hypoxia（P〈0.05）,Y-27632（10^-5mol/L）abolished Ang-Ⅱ induced the increase of the contractile response of VSMC to NE.As compared with the control group,the MLCP activity of VSMC was significantly increased,MLCK activity and phosphorylation of MLC20 were significantly decreased after hypoxia（P〈0.01）.Ang-Ⅱ could decrease hypoxia-induced increase of the activity of MLCP and increase hypoxia-induced decrease of the phosphorylation of MLC20 in VSMC.Ang-Ⅱ（10^-9mol/L）and Y-27632（10^-5mol/L）had no effect on MLCK activity.Conclusion Rho kinase up-regulates the contractile response of VSMC possibly through inhibiting the activity of MLCP and increasing the phosphorylation of MLC20 in VSMC.

关 键 词：RHO激酶 血管平滑肌细胞 肌球蛋白轻链(MLC20) 肌球蛋白轻链磷酸酶(MLCP) 肌球蛋白轻链激酶(MLCK) 

分 类 号：R363[医药卫生—病理学]