小鼠铜绿假单胞菌肺感染中胸腺细胞凋亡的研究

Apoptosis of the thymocytes in mice with pulmonary inflammation induced by Pseudomonas aeruginosa

目的研究铜绿假单胞菌肺部感染与胸腺细胞凋亡的关系及肿瘤坏死因子（ＴＮＦ）介导机制。方法复制铜绿假单胞菌肺部感染动物模型，动态检测感染２４小时内血清，支气管肺泡灌洗液（ＢＡＬＦ）中ＴＮＦ及肺病理变化，同时采用碘化丙啶染色ＤＮＡ含量分析法观察胸腺细胞凋亡情况。结果发现小鼠吸入铜绿假单胞菌３小时后细菌学和病理学检查证实肺部有炎症发生，血清和ＢＡＬＦ中ＴＮＦ开始升高，同时胸腺细胞出现凋亡。在炎症过程中，ＢＡＬＦ及血清中ＴＮＦ升高与胸腺细胞凋亡发生率在动力学基本平行。结论铜绿假单胞菌肺部感染及菌血症可引起胸腺细胞发生凋亡。

OBJECTIVE To investigate apoptosis of the thymocytes in mice with pulmonary inflammation induced by Pseudomonas aeruginosa and TNF-mediated effects was studied.METHODS Pulmonary inflammation models of mice were induced successfully by inhalation of suspension of Pseudomonas aeruginosa. TNF of serum and bronchoalveolar lavage fluid (BALF) were measured 3, 6, 9, 12, 24 hours after inhalation respectively. Apoptosis of the thymocytes were detected with the method of DNA content assay by propidium iodium (PI) staining. RESULTS Pulmonary inflammation were revealed by microbiology and histopathology study 3 hours after inhalation of Pseudomonas aeruginosa. TNF of serum and BALF began to increase at 3h. and reached their highest level at 6h, then decreased to baseline at 24h. Flow-cytometric analysis showed that apoptosis of the thymocytes were similar to TNF of serum and BALF in pattern of kinetics. CONCLUSION The data suggested that Pseudomonas aeruginosa could induce thymocytes apoptosis in mice. TNF is one of the cytokines which mediated pulmonary inflammation and might be responsible for the thymocytes apoptosis. 