Rabbit lung lipids in experimental fibrosis and emphysema: lipolytic activity and content and distribution of lipids

Abstract

Abstract. An in vitro study of lung lipolytic activity in rabbits was performed using tissue homogenates and perfusion methods.Thirty‐two animals were divided into three groups: (a) control; (b) lung fibrosis induced by talc‐powder and (c) lung emphysema group, induced by elastase.In minced lung tissue, incubated with lipid substrate, the release of free fatty acids (FFA) was, in the control group, 5.65 ± 1.12 μmol g wet tissue‐1 h‐1 and in the emphysema group 2.57 ± 0.56 μmol g wet tissue‐1 h‐1, (P < 0.02).Perfusion with lipid substrate did not reveal any significant differences between the three groups with respect to the total quantities of FFA released. It did, however, show that, in the emphysema group, the rate at which FFA were released during the perfusion was slower than in the control group.Moreover, in the emphysema group there was a significant decrease in phospholipid content (control 29.8 ± 1.48 mg/g wet tissue, emphysema 26.1 + 1.14 mg/g wet tissue; P < 0.05), and consequently in total lipids (control 47.1 ± 2.64 mg/g wet tissue, emphysema 38.6 ± 0.24 mg/g wet tissue; P < 0.05) in relation to the control group. The decrease in phospholipids is a consequence of the significant decrease in the lecithin (control 53.7 ± 2.02%, emphysema 43.7 ± 2.40%; P < 0.01) and lysolecithin fractions (control 10.5 ± 1±52%; emphysema 56 + 1.26%; P < 0.05).There were no differences between the control and the fibrotic groups. The lower rate of lung lipolytic activity in the emphysema group may be connected with a decrease in lung lipoprotein lipase (LPL).The low content of lung phospholipids in the cited group may be a result of damaged lung lipolytic activity.