大鼠心肌缺血再灌注后诱发肺组织表达β-防御素-2

摘要

Objective To investigate whether rate lung tissue expresses β-defensin-2 mRNA following myocardial ischemia-reperfusion (I/R). Methods Twelve male Wistar rats (weighed 250-300g) were randomly allocated to one of 2 groups (n=6 each): the myocardial I/R group (group C) and sham operation group (group S). Myocardial I/R was produced by slipknot ligation of the left anterior descending coronary artery (LAD). In group C, LAD was occluded for 45 min followed by 3h reperfusion. A needle suture was threaded through under the LAD but not ligated in group S.All animals were sacrificed by exsanguinations at the end of 3 h reperfusion. The serum, lung tissues and bronchoalveolar lavage (BAL) fluid were collected for determination of MB isoenzyme of creatine kinase (CK-MB), pulmonary permeability index (PPI), Western-blotting of BD-2 and TNI-α proteins, and RT-PCR assay of BD-2mRN A expression.Results The levels of serum CK-MB and PPI were all significantly elevated in group C compared with the group S.The BD-2mRNA expression was significantly higher in group C than in group S, so were levels of the BD-2 and TNFα proteins. There was a positive correlation between levels of BD-2 and TNF-α proteins in group C (r=0.886). Conclusion After myocardial I/R in rats, BD-2 gene expression in lung tissue is up-regulated, along with significant increase in PPI of the lung tissue and levels of BD-2 and TNF-α proteins in the serum.%目的 观察大鼠心肌缺血再灌注后肺组织是否有β防御素-2(BD-2)mRNA的表达.方法 12只健康雄性Wistar 大鼠随机分为2组:心肌缺血再灌注组(C组);假手术组(S组).采用活结结扎冠状动脉左前降支(LAD)的方法制备心肌缺血再灌注模型.C组阻断左前降支45 min后再灌注3 h;S组缝合针仅穿过左前降支下方,不结扎.分别于实验结束时放血处死大鼠,提取肺组织、支气管肺泡灌洗(BAL)液和血清;进而测定血清肌酸激酶同工酶(CK-MB),计算肺通透性指数(PPI),聚合酶链反应(PCR)法测定肺组织BD-2mRNA表达水平,Western-Blot法检测肺组织BD-2和TNF-α蛋白的含量.结果 与S组相比,C组CK-MB和PPI明显升高;β防御素-2mRNA表达上调;同时β防御素-2和肿瘤坏死因子(TNF)-α蛋白含量增加,C组β防御素-2和TNF-α蛋白含量之间呈正相关(r＝0.886).结论 大鼠心肌缺血再灌注后肺组织β防御素-2 mRNA表达上调,同时肺组织PPI升高、β防御素-2和TNF-α蛋白含量也明显增加.