吸入一氧化氮对内毒素性急性呼吸窘迫综合征犬肺炎性反应的影响

Effect of nitric oxide inhalation on pulmonary inflammatory responses in dogs with endotoxin-induced acute respiratory distress syndrome

目的 通过观察吸入一氧化氮(NO)对内毒素性急性呼吸窘迫综合征(ARDS)犬肺组织中肿瘤坏死因子-α(TNF-α)、白细胞介素-8(IL-8)及CD11b mRNA表达的影响,从分子水平探讨吸入NO治疗ARDS的机制。方法 12条毕格犬静脉输注内毒素达ARDS后,随机分成两组,单纯机械通气组(C组,n=6),机械通气+吸入NO组(NO组,n=6),NO吸入浓度分别为10、20、40、80 ppm,按顺序各吸入1 h后,降至10 ppm吸6 h。无菌条件下取肺组织,提取肺组织总RNA,采用逆转录-多聚酶链反应技术检测TNF-α、IL-8、CD11b mRNA表达的水平。结果 C组肺组织中的TNF-α、IL-8及CD11b mRNA表达水平高于NO组(P<0.05)。结论 NO抑制炎性反应可能是其对ARDS产生治疗作用的一个方面。

Objective To investigate the effects of nitric oxide (NO) inhalation on the expression of TNF-α,IL-8 and CD11b mRNA in lung tissue during acute respiratory distress syndrome (ARDS) induced by intravenous injection of endotoxin in dogs.Methods Twelve pure bred beagle dogs of both sexs weighing 8-12.5 kg were randomly divided into 2 groups: NO group received mechanical ventilation with NO inhalation (n = 6) and control group received only mechanical ventilation ( n = 6) . Sepsis and ARDS were induced by intravenous injection of endotoxin as described in detail in our previous paper. Hemodynamics and pulmonary oxygenation were monitored and shunt fraction was calculated. At the end of experiment the animals were sacrificed and lung tissue was obtained aseptically and stored in the liquid nitrogen at - 180℃ . The total RNA was extracted. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of TNF-α,IL-8 and CD11b mRNA. The total RNA was reversely transcripted to cDNA. Then the cDNA was amplified by PCR. The product of PCR was scanned by gel-image analysis system.β-action was used as internal control. Semi-quantitative method was adopted for measurement of TNF-α ,IL-8 and CD11b mRNA expression. Results The expression of TNF-α, IL-8 and CD11b mRNA in lung tissue was significantly decreased in NO group compared with those in control group.Conclusion NO inhalation reduces expression of TNF-α, IL-8 and CDllb mRNA in lung tissue during ARDS induced by intravenous endotoxin.