蛋白激酶C在肺缺血预处理保护中的作用

Protective effect of protein kinase C on lung ischemic preconditioning

目的:建立大鼠肺缺血/再灌注(I/R)损伤模型,探讨蛋白激酶C(PKC)在肺缺血预处理(IPC)保护中的作用。方法:建立在体单侧肺原位I/R模型。50只SD大鼠随机均分为假手术(S)组、I/R组、IPC组、多黏菌素B(PMB)组和缺血预处理加多粘菌素B(IPC+PMB)组5组。实验结束时测定各组肺组织SOD活力、MDA含量、肺湿干重比和肺泡损伤数比值,观察肺超微结构变化。结果:(1)与S组相比,I/R组SOD活力下降,MDA含量升高,肺湿干重比升高,肺泡损伤数比值升高(均P<0.01);与I/R组比较,IPC组SOD活力升高,MDA含量降低,肺湿干重比降低,肺泡损伤数比值降低(均P<0.01);与I/R组比较,PMB组和IPC+PMB组各项指标差异无统计学意义(均P>0.05)。(2)肺组织病理学改变:I/R组、PMB组和IPC+PMB组肺组织损伤明显,IPC组肺组织损伤较I/R组明显减轻,S组肺组织结构基本正常。结论:IPC对肺I/R损伤有明显的保护作用,而且这一作用可被PKC抑制剂PMB抑制。

Objective： To establish lung ischemic reperfusion injury model and to investigate the effect of protein kinase C on protection afforded by lung ischemic preconditioning in rats.Methods： Single lung in situ ischemic reperfusion animal model was used.50 SD rats were randomly divided into 5 groups：sham group（S group）,ischemic reperfusion group（I/R group）,ischemic preconditioning group（IPC group）,polymyxin B group（PMB group） and ischemic preconditioning plus polymyxin B group（IPC＋PMB group）.At the end of the experiment,superoxide dismutase activity,malondialdehyde content,wet to dry weight ratio and injured alveoli rate were measured;lung ultramicroscopic structure changes were observed.Results：（1）Compared with S group,the SOD activity decreased and MDA content,W/D and injured alveoli rate increased in I/R group,respectively（P0.01）;when compared with I/R group,the SOD activity increased,MDA content,W/D and injured alveoli rate decreased in IPC group（P0.01）;there was no significant difference of above assessed indexes among I/R group,PMB group and IPC＋PMB group（P0.05）.（2）Obvious pathological changes of lung were found in I/R group,PMB group and IPC＋PMB group.There was less injury in IPC group,and S group seemed roughly normal.Conclusion： Ischemic preconditioning protects lung from ischemic reperfusion injury,but the effect can be blocked by polymyxin B.