缺血后处理对缺血-再灌注损伤大鼠肺IL-1β mRNA表达的影响及其机制

Effects of ischemic post - conditioning on lung IL - 1β mRNA expression and during ischemia - reperfusion injury in rats

目的 研究缺血后处理对缺血-再灌注损伤（IRI）大鼠肺组织内IL-1β mRNA表达的影响并分析其可能的肺保护作用机制.方法 建立大鼠在体肺脏缺血-再灌注损伤模型,SD大鼠24只,随机分为假手术对照组（Sham组）、缺血-再灌注组（IR组）和缺血后处理组（IPostC组）,每组8只.在体大鼠IR损伤模型制备完成,阻断左肺门终止血供及通气造成左肺缺血,达预定时间后松开阻断带恢复血供及通气,形成再灌注.Sham组将模型制备成功3 h后直接取标本 IR组缺血1 h后再灌注2 h IPostC组缺血1 h后给予重复3次的5 min灌注和5 min缺血的后处理,然后恢复血供及通气行再灌注1.5 h.实验结束后留取左肺组织制作10%的组织匀浆用于测定髓过氧化物酶（MPO）的含量 留取小块肺组织测定肺湿/干质量比（W/D）,并在光镜下观察肺组织的病理变化 用RT-PCR法检测IL-1β m RNA的表达量. 结果与Sham组比较,IR组肺组织中IL-1β mRNA的表达量、MPO的活性及W/D值均明显升高（P〈0.05）,病理学观察显示炎症反应明显加重 IPostC组肺组织中IL-1β mRNA的表达量、MPO的活性及W/D值与IR组相比均明显下降（P〈0.05）,病理学观察显示炎症反应明显减轻 3组间比较,差异均有统计学意义（P〈0.05）.结论 缺血后处理能够明显减轻鼠肺缺血-再灌注损伤,其机制可能与抑制缺血-再灌注损伤大鼠肺组织内IL-1β mRNA的表达有关.

Objective To investigate the effects of ischemic post - conditioning on lung IL - 1β mRNA expression during ischemia - reperfusion injury in rats and the possible mechanisms. Methods 24 rats were randomly allocated to three different groups （ n = 8, each group） after preparation of lung ischemia- reperfusion injury model. （1） Sham group ： only Sham operation （thoracotomy） and no ischemia for 3 h. （2） Ischemia - reperfusion group （ IR group） ： interruption of pulmonary perfusion and ventilation for 1 h followed by reperfusion for 2 h. （3） Ischemic post - conditioning group （ IPostC group）： ischemic post -conditioning （5R/51, three times） between the end of ischemia and the beginning of reperfusion followed by reperfusion for 1.5 h. Small pieces of lung tissue （ about 20 mg） were made into homogenate at the end of experiment. The concentration of MPO in the homogenate was determined. The wet to dry weight ratio （W/D） was also measured at the end of reperfusion. The lung tissue was prepared for light microscopic observation after reperfusion. RT - PCR was used to detect the expression of IL - 1β mRNA in lung tissue. Results There was significant statistical difference among three groups（ P 〈 0. 05 ）. The expression of IL - 1β mRNA, the levels of MPO and W/D significantly increased in IR group compared to Sham group （P 〈 0. 05 ） ;the lung histological examination showed that the inflammation of the lung in IR group was significantly serious than that in Sham group. The expression of IL - 1β mRNA ,the levels of MPO and W/D in the lung in IPostC group were significantly decreased compared to IR group （ P 〈 O. 05 ） ; the lung histological examination showed that the inflammation of the lung in IPostC group was significant compared to IR group. Conclusion Ischemic post - conditioning can significantly reduce lung ischemia - reperfusion injury by inhibiting the expression of IL - 1β mRNA in the lung possibly.