紫杉醇促进心肌细胞微管结构稳定上调HO-1表达预防再灌注损伤的机制研究

Mechanism of paclitaxel promoting microtubule structural stability in cardiac myocytes upregulating HO-1 expression to prevent reperfusion injury

目的:探讨紫杉醇通过上调HO-1表达,促进心肌细胞微管结构稳定预防缺血/再灌注(MI/R)损伤的机制。方法:将大鼠离体的灌注Langendorff心脏随机分为三组:对照组、缺血组、紫杉醇组,15 min的平衡期后,对照组进行120 min的常氧灌注;缺血组,缺血30 min后常氧再灌注120 min;紫杉醇组,缺血30 min后,在使用1μmol/L的紫杉醇常氧再灌注120 min;之后采用免疫组化方法和自由基检测试剂盒检测微管破坏情况,采用蛋白质印迹法研究潜在机制。结果:通过免疫组织化学分析微管形态,在对照组中可见微管结构完整,无明显断裂;在缺血组中可见微管连续中断,微管断裂;在紫杉醇组中可见微管结构基本完整,但微管稍有粗乱。蛋白质印迹分析显示紫杉醇组中JNK1的磷酸化水平显著增加。此外,HO-1的表达水平随着紫杉醇处理而增加,这可以被JNK的特异性抑制剂JNK-IN-8抑制。结论:紫杉醇在缺血时能维持微管结构稳定,通过心肌细胞JNK途径诱导HO-1表达或许是其中机制之一。

Objective:To investigate the mechanism of paclitaxel to prevent ischemia/reperfusion(MI/R)injury by up-regulating the expression of HO-1 and promoting the stability of myocardial microtubule structure.Methods:The isolated Langendorff hearts of rats were randomly divided into control group,ischemia group and paclitaxel group.After 15 minutes of equilibrium period,the control group was perfused with normoxia for 120 minutes.In ischemia group,after 30 minutes,normoxic reperfusion for 120 minutes.In paclitaxel group,after 30 minutes of ischemia,1μmol/L paclitaxel was used for normoxia reperfusion for 120 minutes.After that,microtubule destruction was detected by immunohistochemistry and free radical detection kit,and the potential mechanism was studied by Western blot.Results:The morphology of microtubules was analyzed by immunohistochemistry.In the control group,the microtubule structure was complete without obvious rupture.In the ischemia group,microtubules were continuously interrupted and microtubules were broken.In the paclitaxel group,the microtubule structure was basically intact,but the microtubules were slightly messy.Western blot analysis showed that the phosphorylation level of JNK1 was significantly increased in the paclitaxel group.Furthermore,the expression level of HO-1 was increased with paclitaxel treatment,which could be inhibited by JNK-IN-8,a specific inhibitor of JNK.Conclusion:Paclitaxel can maintain the stability of microtubule structure during ischemia,and the induction of HO-1 expression through the JNK pathway in cardiomyocytes may be one of the mechanisms.