肺炎克雷伯菌肺炎对大鼠胸腺细胞凋亡的影响及机制

Apoptosis and mechanisms of thymus cells in rats induced by Klebsiella pneumoniae infection

目的研究肺炎克雷伯菌肺炎对大鼠胸腺细胞凋亡的影响及机制。方法选择10只6周龄健康SPF级Sprague Dawleg雄性大鼠,构建肺炎克雷伯菌肺炎大鼠模型,另外10只SD大鼠尾对照组。造模第6天取腹腔静脉血进行白细胞和中性粒细胞计数。电镜观察大鼠胸腺组织切片,流式细胞术检测胸腺细胞凋亡情况。免疫组织化学法检测胸腺组织中IL-23、Bcl-2和Caspase-3蛋白水平,免疫共沉淀检测Bcl-2泛素化水平。结果模型组大鼠胸腺组织中白细胞和中性粒细胞数目显著高于对照组(P<0.05)。电镜观察显示模型组大鼠胸腺细胞凋亡情况明显,而对照组无显著凋亡情况,模型组胸腺细胞凋亡指数高于对照组,且具有显著性差异(P<0.05)。模型组大鼠胸腺组织中IL-23和Caspase-3蛋白水平高于对照组、Bcl-2蛋白水平低于对照组,且泛素化水平高于对照组。结论肺炎克雷伯菌肺炎会导致大鼠胸腺细胞凋亡,IL-23/Bcl-2/Caspase-3的级联反应参与其中。

Objective To study the apoptosis and mechanisms of thymus cells in rats induced by Klebsiella pneumoniae infection. Methods 10 male Sprague Dawleg rats aged 6 months were selected to construct the model of Klehsiella pneumoniae, and the other 10 SD rats were chosen as the control group. The blood was taken from the abdominal cavity at the sixth days for leukocyte and neutrophil counting. The apoptosis of thymus cells was detected by electron microscope and apoptosis rate was examined by flow cytomery. The levels of Bcl-2, Caspase-3 and IL-23 in the thymus tissue were detected by immunohistochemical method, and the level of Bcl-2 ubiquination was detected by immunohistochemistry. Results The number of leukocytes and neutrophils in the model group was significantly higher than that in the control group （P 〈 0. 05 ）. The apoptosis of thymus cells in the model group was significantly higher than that in control group. The apoptosis index of the model group was significantly higher than that of the control group （P 〈 0. 05 ）. The levels of Caspase-3 and IL-23 protein in the model group were higher than those in the control group, while the level of Bcl-2 protein was lower than that of the control group. In the meantime, the level of ubiquitination of Bcl-2 was higher than that of the control group. Conclusion Klebsiella pneumoniae pneumonia can lead to the apoptosis of rat thymus cells, and the cascade reaction of IL-23/Bcl-2/Caspase-5 is involved.