Lung lipid composition in zinc-deficient rats

There have been a limited number of studies investigating surfactant lipid changes in lung with trace elements. The present investigation was designed to examine the effect of moderate zinc deficiency on the lipid metabolism in rat lung. We also evaluated whether zinc deficiency, which is a wide-spread problem, could play a role in adult respiratory distress syndrome (ARDS). For that purpose, adult male Wistar rats were fed two diets differing in zinc concentration. The rats were divided into two groups. One group was fed a zinc-deficient diet containing 3 mg Zn/kg, and the other group received a zinc-adequate control diet with 30 mg Zn/kg according to AIN 93-M. After 2 mon of treatment, we observed that in the zinc-deficient group (i) total lipids, phospholipids, and cholesterol increased whereas TG decreased in whole lung; (ii) phospholipid (PC) concentration increased in lamellar bodies and alveolar macrophages and decreased in extracellular surfactant but did not change in microsomes; (iii) protein concentration decreased in whole lung, extracellular surfactant, lamellar bodies, and macrophages; (iv) the incorporation of [Me-14C]choline into PC (phospholipids) of lung slices increased; and (v) the activity of CTP/phosphocholine cytidylyltransferase bound to the microsomes increased in the lung. These results suggest that the lipid concentration in the lung (especially the phospholipids) is modified directly or indirectly by a zinc-deficient diet. In a zinc-deficient diet, the lung changes the pattern of PC for an adaptive or recovery stage. Therefore, zinc deficiency implications are important for the design of therapies and public health interventions involving targeted zinc supplementation for high-risk groups or groups with certain diseases, such as ARDS.