甲基强的松龙对大鼠肺缺血-再灌注损伤中细胞凋亡的影响

Effects of methylprednisolone on pneumocyte apoptosis during pulmonary ischemia/reperfusion injury in rats

目的:研究甲基强的松龙对大鼠肺缺血-再灌注损伤(LIRI)中细胞凋亡的影响,并探讨其可能的机制。方法:雄性SD大鼠42只,随机分为假手术组、肺缺血-再灌注(I/R)组、甲基强的松龙(MP)组,每组在3 h和6 h取标本,用Annexin-V-PI双染法通过流式细胞仪检测肺组织细胞凋亡率,免疫组化法观察肺抑制蛋白κB-α(IκB-α)的表达,计算肺湿质量/干质量比值(W/D)、肺组织损伤定量评价(IQA),观察肺病理形态及超微结构的改变。结果:I/R组与假手术组相比,3、6 h点肺组织凋亡率明显增加,肺组织IκB-α的表达明显下降,W/D、IQA显著升高,差异均有显著性意义(P<0.01);在I/R组3 h点,肺组织凋亡率和IκB-α呈显著负相关(r=-0.8929,P=0.0068),和IQA呈显著正相关(r=0.9714,P=0.0003)。MP组与I/R组相比,3、6 h点肺组织凋亡率明显减少,W/D、IQA呈不同程度降低,差异均有显著性意义(P<0.05),6 h点肺组织IκB-α的表达显著增加(P<0.05),肺组织的病理形态及超微结构损害明显减轻。结论:细胞凋亡参与了LIRI的病理生理过程,早期随着炎症反应的增加,凋亡明显增加。MP早期减少肺组织IκB-α的活化,抑制在I/R中凋亡的发生,从而减轻了肺组织的损伤程度。

Objective：To investigate the effects of methylprednisolone （MP）on pneumocyte apoptosis during lung ischemia/reperfusion injury in rats and to study the possible role of MP in pneumocyte apoptosis. Methods：Forty-two male Sprague-Dawley rats used for unilateral lung ischemia/reperfusion model were randomly divided into three groups：sham operation group（ Sh group）, ischemia/reperfusion group （I/R group） ,and methylprednisolone group（ MP group）. Each group has two subgroups of three hours and six hours. Apoptosis rate in lung tissue was detected by the way of Annexin-V-PI in flow cytometer. Expression of IkB-α in lung was observed by immunohistochemical stain. The index of quantitative assessment of histological lung injury（ IQA）, the wet to dry weight ratio （W/D）, the pathological and ultrastructure changes of lung tissue were measured. Results ： Apoptosis rate, W/D, IQA of lung tissue were significantly higher in I/R group than which in Sh group（P 〈0.01 ）,while the expression of IKB-α in lung was obviously lower in I/R group than which in Sh group（P 〈0.01 ）. Apoptosis rate of lung tissue was significantly correlated with IQA level of lung tissue （r = 0.9714,P = 0.000 3 ）. But it had negative cor-relation between apoptosis rate of lung tissue and IkB-α level of lung tissue（ r = - 0. 892 9 ,P = 0. 006 8 ）. MP group had more significant change in apoptosis rate,the expression of IKB-α,W/D, IQA of lung tissue than which in I/R group（P 〈0.05）. The pathological and ultrastructure changes of lung tissue were bet- ter in MP group than which in I/R group. Conclusion：Cellular apoptosis play more important role in the pathological and physiological process of pulmonary ischemia/reperfusion （I/R）injury. In the early period apoptosis rate changes following the changes of inflammatory reactions. MP inhibits the apoptosis of lung I/R injury, extenuates the degree of lung I/R injury by the possible mechanism of decreasing the activation of IKB-α in the early period of lung I/R injury.