高氧致新生大鼠肺损伤过程中T淋巴细胞动态变化的研究

摘要

目的 探讨高氧致新生大鼠肺损伤过程中T淋巴细胞的动态变化.方法 新生12 h内的SD大鼠随机分为对照组、高氧组,对照组置于正常空气中喂养,高氧组持续暴露于80% ～ 85%氧浓度下.两组分别于第1、4、7、14、21天时提取肺脏、脾脏和胸腺,以常规组织学方法观察肺脏形态结构变化;运用常规计数法检测脾脏中淋巴细胞数量变化;采用流式细胞术检测脾脏中CD4+、CD8+ T细胞的百分比变化;以混合淋巴细胞反应检测脾淋巴细胞对植物血凝素(PHA)和自身肺组织的增殖反应;用常规组织学和免疫组织化学法观察胸腺形态结构变化及增殖细胞核抗原表达和CD4+、CD8+细胞分布.结果 实验4 d时,高氧组CD4+、CD8+淋巴细胞百分比较对照组明显增多(P ＜ 0.01),7 d时CD4+淋巴细胞百分比明显高于对照组(P ＜ 0.01),此后CD4+、CD8+淋巴细胞百分比逐渐下降,到实验21 d时接近对照组.淋巴细胞活检发现,实验4 ～ 7 d时,脾淋巴细胞对自身肺组织和对PHA刺激的增殖反应活性较对照组均明显增高(P均＜ 0.01);14 ～ 21 d时,脾淋巴细胞对自身肺组织刺激的增殖反应活性逐渐下降,但均明显高于对照组(P均＜ 0.01),而对PHA刺激后的增殖反应活性均明显低于对照组(P均＜ 0.01).结论 高氧性肺损伤早期,脾脏中CD4+、CD8+淋巴细胞百分比明显增高,活性逐渐增强;后期,脾脏CD4+、CD8+淋巴细胞数量明显减少,淋巴细胞活性显著减低.高氧性肺损伤过程中有自身反应性T淋巴细胞的参与.%Objective To explore the dynamic change of T lymphocytes in neonatal rats with hyperoxic lung injury. Methods Sixty neonatal SD rats were randomly assigned to the hyperoxic group (the exposure of the high concentraion oxygen with FiO2 of 0.80 ～ 0.85) and the control group (the exposure of the air). The rats were sacrificed at 1 , 4, 7, 14 and 21 days after either hyperoxic or air exposure for observing the pathological changes of lung and spleen tissues examined by the histopathologic method, the amount of spleen lymphocytes calculated by the routine counting method, the ratio of CD4+ and CD8+ spleen lymphocyte subsets counted by flow cytometer (FCM), and the proliferative reaction of spleen lymphocytes with either phytohemagglutinin (PHA) or autologous lung cells as the stimulators detected by the way of the mixed lymphocyte reaction, respectively. Results The total amount of spleen lymphocytes in the hyperoxic group started to increase on day 4 after hyperoxic exposure. The ratios of CD4+ and CD8+were significantly higher in the hyperoxic group than those in the control group on day 4 and 7 after hyperoxic exposure (P ＜ 0.01 for all). After that the ratio of CD4+ and CD8+ tended to decrease gradually, and was close to the ratio of the control group on day 21 after hyperoxic exposure. The responses of spleen lymphocytes to either autologous lung cells or PHA were significantly higher in the hyperoxic group than those in the control group during day 4 to day 7 after hyperoxic exposure (P ＜ 0.01 for all), and then the response to both stimulators decreased gradually, in particular the activity of splenocyte responder cells with PHA as the stimulator declined significantly during day 14 to day 21 after hyperoxic exposure (P ＜ 0.01). Conclusions The quantity and the activity of CD4+ and CD8+ spleen lyrmphocytes significantly increase in the early stage and decrease in the later stage of hyperoxic lung injury. The autoreactive T cells may involve in the pathogenesis of hyperoxic lung injury.