Invasion of leukocytes into the alveolar space in LPS-induced ARDS. A. In ARDS, leukocytes migrated into the alveolar space in all groups (*, NaCl; **, LCT; ***, LCT/MCT; § LCT/MCT/FO). After 24 h of LPS-stimulation the LCT group displayed an increased number of leukocytes compared to the NaCl group ($). Mice receiving LCT/MCT/FO infusions displayed the lowest number of alveolar leukocytes at all time-points after LPS stimulation compared to all other groups (%). B. The percentage of lymphocytes, monocytes/macrophages (M/M) and polymononuclear cells (PMN) was calculated in the BAL of all treatment groups and time-points. The time course for the NaCl group is shown but the same pattern was detectable for all other groups. C. Myeloperoxidase (MPO) activity as a marker of PMN invasion increased significantly after 24 h and 48 h in the NaCl group (*) and all other groups compared to control (**, LCT; ***, LCT/MCT; § LCT/MCT/FO). A total of 24 h after ARDS, the LCT group displayed the highest MPO activity of all groups ($). After 48 h, MPO activity was the lowest in animals receiving LCT/MCT/FO as compared to all other groups (%). D. In all groups a significant increase in protein extravasation 4 h, 24 h and 48 h after induction of ARDS could be observed, which was valid for NaCl (*) and the other groups (**, LCT; ***, LCT/MCT; § LCT/MCT/FO). After 48 h of LPS challenge, the mice receiving LCT/MCT/FO showed significantly reduced levels of protein leakage as compared to NaCl-, LCT-, and LCT/MCT-infused mice at this time-point (%). Data are given as mean ± SEM (n = 6 to 8 independent experiments each). All markers indicate P <0.05. ARDS, acute respiratory distress syndrome; BAL, bronchoalveolar lavage; FO, fish oil; LCT, pure long-chain triglycerides; LPS, lipopolysaccharide; MCT, medium-chain triglycerides; MPO, myeloperoxidase.