创伤性休克致急性肺损伤大鼠肺泡巨噬细胞TNF-α IL-18mRNA表达的变化及地塞米松的影响

Expression of TNF-α、IL-18mRNA in alveolar macrophages of rats with acute lung injury induced by trauma combined with hemorrhagic shock and effects of dexamethasone on this event

目的 探讨创伤性休克致急性肺损伤大鼠肺泡巨噬细胞TNF -α、IL - 18mRNA表达水平的变化及地塞米松对其的影响。方法 将大鼠随机分为正常对照组、创伤性休克生理盐水处理组、创伤性休克地塞米松治疗组 3组 ,在创伤性休克打击前予地塞米松 (10mg/kg)对治疗组预处理 ,测定正常对照组、创伤性休克生理盐水处理组及地塞米松治疗组 1、2、4、6、8h各时点肺泡巨噬细胞TNF -α、IL - 18mRNA表达水平。结果 大鼠遭受创伤性休克打击后 ,肺泡巨噬细胞TNF -αmRNA表达明显增加 ,2h即达高峰 (P <0 0 1) ,然后逐步下降 ,但 8h仍高于正常水平 (P <0 0 5 ) ;IL - 18mRNA表达亦显著增加 ,4h达高峰 (P <0 0 1) ,然后逐步下降 ,8h恢复至正常水平 ;地塞米松能显著降低肺泡巨噬细胞TNF -α、IL - 18mRNA的峰值浓度及各时点值 ,并能一定程度改善PaO2 及肺组织损伤。结论 创伤性休克早期大鼠肺泡巨噬细胞TNF -α、IL - 18mRNA表达均增加 ,地塞米松能抑制TNF -α、IL - 18mRNA的表达 ,在ALI早期应用能减轻病变。

Objective To investigate changes of TNF-α、IL-18mRNA in alveolar macrophages(AM) of rats with acute lung injury(ALI)induced by trauma combined with hemorrhagic shock and effect of dexamethasone(DXM) on its expression.Methods We randomly divided rats into three groups:normal control group;sham-treated group of ALI and dexamethasone-treated group of ALI(ALI-DXM),which pretreated the rats with DXM(10 mg/kg) before trauma combined with hemorrhagic shock.Using semi-quantitative reversal-transcription polymerase chain reaction(RT-PCR) technology,TNF-α、IL-18mRNA in AM of rats were measured.Meanwhile,the pathological changes of lung were examined by light microscope and PaO_2 and lung wet/dry ratio were determined.Results AM of normal rats expressed TNF-α、IL-18mRNA in some extent;expression of TNF-α increased quickly with peak levels being present at 2 h after trauma combined with hemorrhagic shock, and decreased regularly but stayed beyond baseline levels at 8 h. Meanuhile, IL-18 mRNA increased with peak levels being present at 4 h after trauma combined with hemorrhagic shock,and returned to baseline levels at 4 h.The administration of DXM inhibited the expression of TNF-α、IL-18mRNA and alleviated the pulmonary tissue damage.Conclusion After hitting by trauma combined with hemorrhagic shock,the expression of TNF-α、IL-18mRNA increased abnormally.DXM had a protective effect on rats with ALI induced by trauma combined with hemorrhagic shock maybe by down-regulating of the expression of TNF-α、IL-18mRNA in AM.