老年多器官功能障碍综合征肺组织IL-6的变化

Changes and significance of IL-6 in lung tissue of elderly rats model of multiple organ dysfunction syndrome

目的探讨肺组织中IL-6含量及mRNA表达在老年大鼠多器官功能障碍综合征(Multiple organ dysfunctionsyndrome,MODS)中的变化。方法80只SD大鼠分为老年组(20月龄)和青年组(3月龄)各40只,建立油酸/脂多糖(OA/LPS)二次致伤老年MODS和青年MODS模型。观察对照组及伤后2、6、24 h,重要器官(肺、心、肝、肾)病理及功能的变化,通过ELISA方法检测上述组织中IL-6含量,IL-6 mRNA表达用RT-PCR法检测。结果OA/LPS二次致伤MODS模型,肺脏是损害出现最早也是最重的器官,致伤后2 h青年组和老年组PaO2即下降至最低值,伤后6 h,心、肝、肾生化指标达峰值,在相同时相点老年鼠脏器损害重于青年鼠。致伤2h后肺、心、肝和肾组织中IL-6 mRNA表达及蛋白含量均升高,且持续高于正常对照组,以肺组织中升高幅度最大,老年组高于同时相点青年组。结论老年MODS过程中肺损伤出现最早且严重,其原因可能与OA/LPS致伤早期老年鼠肺组织中IL-6 mRNA表达及蛋白含量迅速升高有关。

Objective To study the change and significance of interleukin-6 （IL-6） in lung tissue of elderly rats model of multiple organ dysfunction syndrome （MODS） . Methods MODS models in the elderly （20 months old） and in the young rats （3 months old） were established by injection of oleic acid （OA） at the dose of 0. 25 ml/kg and lipopolysaccharlde （LPS） at dose of 3, 5mg/kg into SD rats （4 h interval）. They were randomly divided into four groups respectively ： control group and three model groups （n=10 for each group）. The changes of pathomorphology and function in the lung, heart, liver and kidney were observed. The IL-6 contents in plasma and in the lung, heart, liver, and kidney were determined by enzyme linked immunosorbent assay （ELISA）. Seml-quantitative RT-PCR was used to measure mRNA expression of IL-6 mRNA in lung, heart, liver and kidney tissues. Results After OA and LPS injection, the lung impairment appeared firstly and PaO2 decreased to minimum at 2 h. Biochemical indexes of functional lesion of the heart, liver and kidney increased to the peak level at 6h. Organs injured more seriously in elderly group than young group at the same time points. The expression of IL-6 mRNA and the concentration of IL-6 in different tissues increased significantly 2 h after LPS injection. Among them, lung tissue was most evidently increased. The expression of IL-6 mRNA in different tissues was higher in elderly group than in young group at the same time points. Conclusion IL-6 level and its mRNA expression evidently rise at early time in lung tissues of elderly rats after OA and LPS injection, which may explain the reasons that the lung injured firstly and more seriously in elderly rats with MODS.