叶酸对大鼠肺缺血再灌注损伤的保护作用

目的: 探讨叶酸对大鼠肺缺血再灌注损伤的影响。方法: 选取健康成年雄性SD大鼠30只，随机均分为5组，每组6只，其中3组叶酸组分别以5、10、20 mg/d叶酸灌胃1周；然后叶酸组及缺血再灌注组大鼠构建肺缺血再灌注模型，夹闭左肺门30 min，再灌注2 h；假手术组游离左肺门不夹闭；HE染色观察每组大鼠肺组织病理变化；ELISA法测定大鼠血清IL-8和TNF-α水平。结果： 与假手术组比较，缺血再灌注组大鼠肺组织病理损伤明显较重(P<0.01)；与缺血再灌注组比较，叶酸组肺组织病理损伤明显较轻(P<0.01)；与5 mg/d叶酸组比较，10 mg/d与20 mg/d叶酸组肺组织病理损伤明显较轻(P<0.01)，而后两组比较未见显著性差异(P>0.05)。与假手术组比较，缺血再灌注组、叶酸组IL-8和TNF-α表达水平均明显增高(P<0.01)；与缺血再灌注组比较，叶酸组IL-8和TNF-α表达水平明显降低（P<0.01）；与5 mg/d叶酸组比较，10 mg/d与20 mg/d叶酸组TNF-α表达水平明显降低(P<0.05)，而后两组比较差异无统计学意义(P>0.05)；叶酸组IL-8 水平降低呈一定的剂量依赖性(P<0.05)。结论： 叶酸对大鼠肺缺血再灌注损伤有一定的保护作用，且在一定范围内随叶酸剂量的增加而增强。

Protective effect of folic acid on lung ischemia-reperfusion injury in rats

Objective: To explore the effect of folic acid on lung ischemia-reperfusion injury in rats. Methods: Thirty healthy adult male SD rats were randomly divided into 5 groups with 6 rats in each group, of which 3 groups were gavaged with folic acid at doses of 5, 10, 20 mg/d for 1 week. Then, the folic acid groups and ischemia-referfusion group rats were constructed a model of lung ischemia-reperfusion, in which the left hilum was clamped for 30 min and reperfused for 2 h; sham operation group the left hilus was dissociated but not clamped. The pathological changes of lung tissue was observed by HE staining; the level of IL-8 and TNF-α were determined by ELISA. Results: Compared with the sham operation group, the lung injury severity  in the ischemia-reperfusion group was significantly serious (P<0.01); compared with the ischemia-reperfusion group, the severity in the three folic acid groups was significantly alleviated; compared with the 5 mg/d folic acid group, 10 mg/d and 20 mg/d folic acid groups had significantly less pathological lesions in the lung tissue(P<0.01), while there was no significant difference between the later two groups(P>0.05). Compared with the sham operation group, the level of IL-8 and TNF-α in the ischemia-reperfusion group and the folic acid groups was remarkably higher(P<0.01); compared with the ischemia-reperfusion group, the level of IL-8 and TNF-α in the three folic acid groups was markedly lower (P<0.01); compared with the 5 mg/d folic acid group, the level of TNF-α in 10 mg/d and 20 mg/d folic acid groups was greatly lower; while there was no significant difference between the later two groups(P>0.05); the decrease of IL-8 level in the three folic acid groups was in a dose dependent manner(P<0.05). Conclusion: Folic acid exerts protection on lung ischemia-reperfusion injury in rats. ［Key words］folic acid; lung ischemia-reperfusion injury; IL-8; TNF-α; rat