中性粒细胞活化在呼吸机所致肺损伤中的作用

目的探讨中性粒细胞活化在呼吸机所致肺损伤中的作用。方法32只Wistar大鼠随机分为对照组、小潮气量组、常规潮气量组和大潮气量组。分别测定支气管肺泡灌洗液(BALF)中白细胞及中性粒细胞计数,血浆和BALF中蛋白含量及髓过氧化物酶(MPO)活性。结果常规潮气量组和大潮气量组大鼠BALF中白细胞及中性粒细胞计数、BALF中MPO活性和蛋白含量均明显高于对照组和小潮气量组(P<0.05或P<0.01),大潮气量组大鼠BALF中MPO活性和蛋白含量均明显高于常规潮气量组(P均<0.01),对照组和小潮气量组间比较差异均无显著性(P均>0.05)。各组大鼠间血浆MPO活性和蛋白含量比较差异均无显著性(P均>0.05)。结论中性粒细胞募集和活化在呼吸机所致肺损伤中起着重要作用,BALF中MPO活性是反映中性粒细胞活化程度的可靠指标,BALF中蛋白含量测定对评价肺损伤程度有实用价值。

Role of neutrophil activation in ventilator induced lung injury

Objective To probe further the role of neutrophil activation in the lung injury induced by mechanical ventilation. Methods Thirtytwo normal Wistar rats were randomly divided into four groups: control group,low tidal volume group,conventional tidal volume group, and high tidal volume group. The counts of white blood cell (WBC) and neutrophil in bronchoalveolar lavage fluid (BALF) were carried out. The levels of protein and myloperoxidase(MPO) activity in plasma and BALF were determined by biochemicalmethods respectively. Results The numbers of WBC and neutrophils, and the levels of protein and MPO activityin BALF were significantly increased in normal and high tidal volume groups than those in control and low tidal volume groups(P<0.05 or P<0.01, respectively). The levels of protein and MPO activityin BALF in high tidal volume group were markedly higher compared with normal tidal volume group(both P<0.01), but no statistical differences existed between the low tidal volume group and the control group (both P>0.05). There were no significant differences in the levels of protein and MPO activity in plasma among the four groups(P>0.05). Conclusion The recruitment and activation of neutrophils might play an important role in pathogenesis of the biotrauma induced by mechanical ventilation. MPO activity in BALF is a credible index in reflecting the activation of neutrophils. Measuring the level of protein in BALF is valuable to evaluate the extent of lung injury induced by mechanical ventilation.