循环和肺巨噬细胞极化在潜水减压性肺损伤致病中的作用研究

Bubbles in the circulation and tissues after diving are a major factor related to the duration of decompression, and lung is a target organ of bubbles in the circulation. Even decompression according to standard decompression schedule will cause lung injury to a certain extent. Studies have shown that circulating and lung macrophage polarization are involved in the pathogenesis of some pulmonary diseases, but its role in the pathogenesis of decompression related lung injury is still unclear. Our pilot study showed the circulating macrophages were induced to M1 phenotype (pro-inflammatory) in rats after rapid decompression (flow cytometry) and the cytokines that can induce this phenotype also increased significantly in these rats, but IL-10 (a cytokine that can inhibit the M1 polarization) was able to reverse above changes. This study was undertaken in rapid decompression rat model and in vitro bubble-treated cell model to systemically investigate the role of circulating and lung macrophages in the decompression related lung injury by histology, flow cytometry, molecular biology, co-culture and fluorescence labeling technique. Our results will provide experimental evidence on the role of macrophages in decompression induced lung injury and also present a new target for the prevention of this disease.

潜水后循环和组织中产生的气泡是导致减压时间延长的主要因素，而肺是气泡的一个靶器官，即使是正常减压也会导致一定程度的肺损伤。研究显示，循环和肺内巨噬细胞极化参与了诸多肺部疾病的致病，但它与减压相关肺损伤的关系尚不清楚。我们前期研究显示，快速减压大鼠循环和肺内诱导巨噬细胞向M1型（促炎）转化的细胞因子产生显著增加，流式细胞检测也证实循环M1型巨噬细胞比例显著增加，而给予加压治疗和抑制M1转化的细胞因子（IL-10）则能逆转上述表现。本实验拟在大鼠快速减压模型和体外气泡刺激模型中，通过组织形态学、流式细胞分析、分子生物学、共培养以及荧光标记等技术，全面分析循环和肺巨噬细胞极化在减压相关肺损伤中的作用。本研究结果将为巨噬细胞在减压相关肺损伤致病中的作用提供实验证据，也为减压病的预防提供新的治疗靶点。

潜水后减压，体内会产生一定量的气泡（主要产生与静脉系统）。由于肺是气泡的一个靶器官，即使是不会造成机体临床表现，也会对肺造成一定的损伤，称之为减压诱导肺损伤（decompression-induced lung injury，DILI）。减压诱导肺损伤是威胁潜水人员健康的重要医学问题。目前，DILI的具体机制尚不清楚。巨噬细胞极化在诸多肺部疾病的致病中都发挥了重要作用。我们推测，减压后静脉内产生的气泡导致巨噬细胞活化，与DILI的致病有密切关系。本文构建减压性肺损伤模型，并进一步研究巨噬细胞极化在减压性肺损伤中的作用。.大鼠单次5 ATA下暴露40 min后快速减压，在未发生减压病的情况下，存在肺功能下降，主要表现为肺阻力的下降，同时血气分析结果存在改变，表现为氧合下降，二氧化碳增加，血液炎症因子表达升高。这些表现再24 h后趋于缓解。小鼠单次减压并不会引起肺功能的明显改变。小鼠反复减压后肺功能持续下降，表现为肺总量（total lung capacity，TLC）、肺顺应性（chord compliance，Cchord）、功能余气量（functional residual capacity，FRC）的持续下降，第三次达到最低值。减压后小鼠肺干湿比上升，肺泡灌洗液中伊文思蓝的含量上升，H&E染色表明，减压引起肺组织紊乱，炎细胞浸润，减压次数越多组织学评分越低。ELISA实验结果表明，循环和肺内的TNF-α、IL-10、ICAM-1和MCP-1含量在减压后上升，减压次数越多，升高的越明显。小鼠肺内F4/80、CD206和iNOS蛋白表达逐日上升，第三次减压后达到峰值。免疫组化结果表明，减压后小鼠肺内F4/80、CD206和iNOS的阳性细胞数量上升，肺内CD206和iNOS的mRNA表达水平升高。