Role of active nitrogen oxide in cell stretch-induced pulmonary alveolar injury.

以潮气量30 ml/kg体重、PEEP 0 cmH_2O通气，可诱发以中性粒细胞浸润和肺泡液潴留为特征的呼吸机诱导性肺损伤（VILI）。用内毒素（LPS，1 mg/kg体重）预处理增强VILI。VILI肺支气管肺泡灌洗液（BALF）中NO_2和NO_3浓度均显著高于自主呼吸和潮气量10 ml/kg体重时的BALF，用特异性诱导型一氧化氮合酶（iNOS）抑制剂ONO-1714预处理可剂量依赖性地减轻VILI; BALF中NO_2/110_3浓度和中性粒细胞计数均较未治疗组显著降低，而超氧化物歧化酶（SOD）预处理对VILI的组织病理学改变无明显影响，BALF中性粒细胞计数和NO_2/NO_3浓度均较未处理的VILI组降低，iNOS蛋白和iNOS mRNA表达均较对照组增强，肺泡Ⅱ型细胞从大鼠肺分离Ⅱ型细胞，以15次/min的速率对Ⅱ型细胞施加30- 50cmH_2O压力3 h。培养的Ⅱ型细胞上清中NO_2/NO_3浓度随压力负荷的增加而显著升高。与未处理的II型细胞相比，压力负荷后II型细胞凋亡率显著增加，NF-κB活化显著增强。ONO-1714预处理可显著抑制压力负荷诱导的II型细胞凋亡率的增加，并有减弱NF-κB活化的趋势。3产物参与细胞牵张和/或变形引起的肺损伤。

When rats were ventilated with a tidal volume of 30 ml/kg body weight and a PEEP of 0 cmH_2O, ventilator-induced lung injury (VILI) was induced, which was characterized by neutrophil infiltration into alveoli and retention of alveolar fluid. Pretreatment with endotoxin (LPS, 1 mg/kg body weight) augmented VILI. Both NO_2 and NO_3 concentrations in broncho-alveolar lavage fluid (BALF) from VILI lungs were significantly higher than those from spontaneous breathing or a tidal volume of 10 ml/kg body weight.Pretreatment with ONO-1714, a specific inducible nitric oxide synthase (iNOS) inhibitor, attenuated VILI in a dose-dependent manner ; both neutrophil count and NO_2/110_3 concentrations in BALF were significantly decreased compared with untreated VILI.Pretreatment with superoxide dismutase (SOD) did not change histopathological findings of VILI significantly, however, both neutrophil count and NO_2/NO_3 concentrations of BALF tended to be reduced compared with untreated VILI.Expression of both iNOS protein and iNOS mRNA were augmented in VILI compared with control lungs.Alveolar type II cells (type II cells) were isolated from rat lungs, and a pressure of 30-50 cmH_2O at a rate of 15 times/min for 3 hours was applied on those type II cells. NO_2/NO_3 concentrations in supernatant of cultured type II cells were significantly elevated in response to pressure load. Frequency of apoptosis of pressure-loaded type II cells was significantly increased and activation of NF-κB was significantly augmented compared with untreated type II cells.Pretreatment of type II cells with ONO-1714 significantly inhibited increment of apoptosis and tended to attenuate activation of NF-κB induced by pressure load.These results indicated that expression of iNOS and subsequent NO_2/NO_3 production were involved in lung injury induced by cell stretch and/or deformity.