内毒素肺损伤大鼠CD4^+T细胞凋亡的变化及其作用探讨

Apoptosis of CD4^+T cells and its effects in lipopolysaccharide-induced acute lung injury in rats

目的 观察外周血与支气管肺泡灌洗液 (BALF)中CD4 + T淋巴细胞凋亡变化 ,以进一步认识ALI的发生机理。方法 静脉注射脂多糖制作大鼠内毒素肺损伤模型。分离、提纯外周血与BALF中T淋巴细胞 ,抗大鼠CD4 :FITC单克隆抗体标记后 ,通过流式细胞仪检测及荧光显微镜检查 ,观察外周血与BALF中CD4 + T淋巴细胞凋亡变化。结果 脂多糖 (LPS)致伤后 ,外周血与BALF中CD4 + T淋巴细胞进行性减少 ,与正常对照组比较差异非常显著 ,与该类细胞凋亡比例之间呈显著负相关关系 ,提示CD4 + T细胞呈时间依赖性凋亡性减少。地塞米松 (DEX)组与LPS组比较 ,CD4 + T细胞比例及凋亡百分数无显著差异。结论 CD4 + T细胞凋亡可能部分参与内毒素肺损伤的发生 ,DEX的治疗作用与CD4 + T细胞凋亡可能无关。

Objective To investigate apoptosis of CD4 +T lymphocytes in peripheral blood and in BALF in lipopolysaccharide induced acute lung injury rat models and to evaluate the mechanism of acute lung injury.Methods Acute lung injury rat models were developed by applying LPS venous injection.T lymphocytes in peripheral blood and in BALF were separated and purified.After T lymphocytes were labelled with Anti rat CD4:FITC monoclone antibody,apoptosis of CD4 +T lymphocytes was detected by flow cytometry and fluorescence microscopy.Results After LPS challenge,the percentage of CD4 + T cells in peripheral blood and in BALF was gradually decreasing as compared with that of normal control.The relative analysis showed a significant negative correlative relationship between the percentage of CD4 +T cells and proportion of the apoptotic cells among them,indicating that the number of CD4 +T cells decreases in time dependent manner because of apoptosis.Comparied with LPS group,no significant difference exists in DEX(Dexamethasone) group.Conclusion These results indicate that apoptosis of CD4 + T cells may be partly attributable to the development of lipopolysaccharide induced acute lung injury.The therpeutical effects of DEX may be no related to CD4 + T cell apoptosis.