The Effects of Nitric Oxide and Sphingosine 1-phosphate on the Pulmonary Microstructure in a Rat Model of Acute Lung Injury: An Intravital Videomicroscopic Approach / 대한흉부외과학회지

ABSTRACT

BACKGROUND: To evaluate the effects of inhaled nitric oxide (NO) and sphingosine 1-phosphate (S1P) as potential therapeutic agents of acute lung injury, we analyzed the morphology in vivo of the pulmonary microstructure using intravital videomicroscopy in a rat model of acute lung injury. MATERIAL AND METHOD: Sprague Dawley rats were divided into five groups a control group that underwent normal saline aspiration, an acute lung injury (ALI) group that underwent hydrochloric acid aspiration, and three treatment groups that underwent hydrochloric acid aspiration and were administered therapeutic agents- the S1P group, the NO group, and the S1P+NO group (n=7 per group). To quantify alveolar compliance and interstitial edema, the diameters of all measurable alveoli and interalveolar septa were averaged at one and two hours after aspiration. Alveolar compliance was determined according to diameter changes during the respiratory cycle and the change in tidal volume. RESULT: At two hours after aspiration, the mean alveolar compliance (% change) in the ALI group decreased significantly versus the control group of rats (respiratory cycle 1.9% for the ALI group vs 6.5% for the control group, p=0.03; tidal volume 3.2% for the ALI group vs 9.1% for the control group, p=0.003) and versus the NO group (tidal volume 3.2% for the ALI group vs 16.9% for the NO group, p=0.001). At two hours after aspiration, the mean interalveolar septal thickness in the NO group tended to be smaller as compared to that in the ALI group (15.2micrometer for the ALI group vs 12.3micrometer for the NO group, p=0.06). S1P did not exert a significant effect on the pulmonary microstructure of the injured rat lung. CONCLUSION: Improved alveolar compliance and reduced interstitial edema, observed by intravital videomicroscopy, suggest that inhaled NO ameliorates lung injury.