Objective: To investigate the potential role of polymorphonuclear neutrophil(PMN) apoptosis in the development of rabbit acute lung injury(ALI). Methods; Thirty-six healthy New Zealand white rabbits were randomly divided into control group( n =6) and burn group (5 time points including 2,4,8,12,24 hours after burn, with 6 in each time point). The pathological changes of lung tissue were observed. Lung injury scores ( LIS) and wet-dry weight ratio ( W/D) of rabbit lung tissue were calculated. PMNs were isolated and purified in bronchoalveolar lavage fluid. PMN apoptosis, necrosis, survival cell ratio and the changes of respiratory burst function were measured by flow cytometry. Results; There were significant changes in pathological section of rabbit lung tissue in burn groups at different time. It was observed that alveolar spaces and interstitial edema were occurred with massive infiltration of PMN, pulmonary architecture was damaged at 2 hours, and worsened with prolongation of time. LIS and W/D were increased at 2 hours and reached the peak at 24 hours,the differences were significant after 8 hours between control group and burn group(P 0.05). PMN survival rate in the 5 burn groups was higher than in control group (P 0.05),但与对照组比较差异均有统计学意义(P0.05);烧伤组PMN的存活率均显著高于对照组(P<0.01);PMN呼吸爆发在烧伤2 h后升高,8 h到达峰值(P<0.01),后下降至对照组水平.结论:ALI兔PMN从血管游出到达肺组织,在肺泡中大量聚集,且凋亡途径发生障碍,致PMN持续处于活化状态,与ALI的发病相关.
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