Effect of malnutrition on lung phospholopid, pressure-volume curve and arterial blood gases: experimental study in rats

RESUMO

In order to study the effects of chronic malnutrition on lung surfactant, adult male Wistar rats reciving a standard diet (SD) were comparaed to animals submitted to food restriction (FR). SD rats given food and water and libitum and FR rats were allowed half (10g) of their usual food comsumption and water ad libitum, for 28 days. the evaluation of the pulmonary surfactant included pressure-volume curve with air inflation, pH and artherial blood gas measurements with rats breathing room air and 100 percent oxygen and determination of phospholipids in the lung washouts. In the pressure-volume curve, the volumes retained at 5 and 10 cmH2O of transpulmonary pressure (Tpt) and the Tpt of 40 percent of total lung capacity (TLC) were not significantly different between the two groups, showing that food restriction did not increase the surface forces. the increase in TLC/lung wet weight ratio in the FR group, probably was secondary to decrease in the elastic recoil forces in the lungs. The PaO2 did not show any significant difference between the groups. The arterial blood pH and PCO2 were also similar in both, SD and FR groups. Total phospholipid content in the lung washouts related to be weight was not signifiantly different in SD as compared with FR rats. Therefore, in this malnutrition model of rats, no alterations in pulmonary surfactant could be shown