Hypercholesterolemia does not affect pulmonary surfactant or the development of acute lung injury in rats

Abstract

Pulmonary surfactant is a lipoprotein complex necessary for lung function. The importance of surfactant is evident in Acute lung injury (ALI) in which the dysfunction of surfactant is thought to contribute to the hypoxemia characterizing the disease. Recent studies have specifically implicated elevated levels of cholesterol within surfactant as a mechanism for its dysfunction. It is not known if this effect is dependent on serum cholesterol. It was hypothesized that diet‐induced serum hypercholesterolemia affects surfactant composition and will cause development of more severe ALI. Wistar rats were fed a standard laboratory diet or high cholesterol diet prior to enrollment into one of three models of ALI: a ventilator induced lung injury model, a surfactant depleted lung injury model and an acid aspiration lung injury model. For each model measurements of lung injury, such as arterial oxygenation, as well as surfactant composition were measured. Results of this study indicated there were no significant differences in arterial oxygenation or surfactant composition between rats fed the standard diet versus the high cholesterol diet in any of the models of lung injury. In conclusion, these three complementary models of ALI suggest that diet‐induced serum hypercholesterolemia does not affect surfactant composition or the development of ALI. Funding was provided by the Canadian Institutes for Health Research.