肌球蛋白轻链激酶在失血性休克大鼠离体淋巴管收缩性双相变化中的作用  

Role of myosin-light-chain kinase in biphasic contractile activity of lymphatics isolated from hemorrhagic shock rats

作　　者：张玉平[1] 牛春雨[1] 赵自刚[1] 秦立鹏[1] 司永华[1] 张立民[1] 张静[1] 

机构地区：[1]河北北方学院微循环研究所,基础医学院病理生理学教研室,河北张家口075000

出　　处：《中国病理生理杂志》2012年第4期589-594,共6页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.30770845);河北省自然科学基金资助项目(No.C2008000503);河北省教育厅科学研究重点项目(No.ZH2007101);河北省百名优秀人才支持计划(No.CPRC047)

摘　　要：目的:探讨肌球蛋白轻链激酶(MLCK)在失血性休克(HS)大鼠离体淋巴管收缩性双相变化中的作用机制。方法:Wistar雄性大鼠随机均分为对照组和HS组(复制HS模型,分为HS 0 h、0.5 h、1 h、2 h和3 h亚组),留取胸导管组织,检测磷酸化MLCK(p-MLCK)含量;制备对照、HS 0.5 h与2 h组的淋巴管条,采用离体淋巴管收缩性观察技术,观察MLCK抑制剂ML-7和激动剂P物质(SP)对HS 0.5 h及2 h淋巴管收缩频率(CF)、收缩末期直径、舒张末期直径和被动直径的影响,计算淋巴管紧张性指数(TI)、收缩幅度(CA)和泵流分数(FPF),评价淋巴管收缩性。结果:HS 0 h和0.5 h淋巴管组织p-MLCK蛋白显著高于对照组;随着休克发展,p-MLCK含量逐渐降低。在1、3、5 cmH2O等多个跨壁压下,HS 0.5 h组淋巴管的CF、TI和FPF均显著高于对照组,ML-7可显著下调这些指标,SP则可明显降低ML-7的作用,使之恢复至HS 0.5 h水平;HS 0.5 h组淋巴管的CF、TI和FPF均显著低于对照组,SP可显著上调这些指标,ML-7则可显著降低SP的作用。HS 0.5 h与2 h离体淋巴管CA与对照组相比无显著变化,SP可降低HS 2 h淋巴管的CA,ML-7可抑制该作用,但二者对HS 0.5 h无明显作用。结论:MLCK作为影响淋巴管平滑肌细胞收缩的关键酶,参与了HS发展进程中淋巴管收缩性的双相调节。AIM： To elucidate the mechanism by which myosin-light-chain kinase（MLCK） modulates the biphasic contractile activity of lymphatics isolated from the rats subject to hemorrhagic shock（HS）.METHODS： Male Wistar rats were randomiz to control group and HS group.In HS group,the rats were subject to HS and then further divided into HS 0 h,0.5 h,1 h,2 h and 3 h subgroups.Thoracic ducts of control and shock rats were isolated and used to determine the protein levels of phosphorylated MLCK（p-MLCK）.In addition,thoracic ducts obtained from control,0.5 h-and 2 h-shocked rats were used to observe the contractile properties of lymphatics by a pressure myograph in vitro.Lymphatic rings were prepared and incubated with ML-7（a specific inhibitor of MLCK） or substance P（SP,an agonist of MLCK）.During the experiment,the contractile frequency（CF）,end-diastolic diameter,end-systolic diameter and passive diameter in Ca2＋-free PSS buffer were measured and used to calculate the lymphatic tonic index（TI）,contractile amplitude（CA） and fractional pump flow（FPF） as the indexes of lymphatic contraction activity.RESULTS： The levels of p-MLCK in lymphatics in 0 h-and 0.5 h-shocked rats were significantly increased compared with the control rats,and it was gradually decreased with the development of shock.The values of CF,TI and FPF in 0.5 h-shocked lymphatics were significantly increased at transmural pressure of 1,3 and 5 cmH2O compared with those in control group,and significantly blunted by ML-7.SP obviously increased the suppressive effects induced by ML-7 and restored the values of CF,TI and FPF to the levels of HS 0.5 h group.CF,TI and FPF in 2 h-shocked lymphatics significantly declined under different transmural pressure as compared with those in control group,and significantly elevated by SP.Similarly,ML-7 depressed the effects of SP.No significant difference was found in CA between 0.5 h-and 2 h-shocked lymphatics.SP decreased the CA of lymphatics obtained from 2 h-shocked rats and this effec

关 键 词：休克 出血性 淋巴管 收缩性 肌球蛋白轻链激酶 

分 类 号：R364.14[医药卫生—病理学]