Effect of fish oil containing parenteral lipid emulsions on neutrophil chemotaxis and resident-macrophages' phagocytosis in rats.

BACKGROUND & AIMS: There is scarce information about immune function and parenteral fish oil (FO). The influence of a new parenteral lipid emulsion (LE) containing fish oil (SMOF) was experimentally evaluated on neutrophils' chemotaxis and macrophages' phagocytosis.

METHODS: Adult male Lewis rats (n=40) were randomized into five groups; one non-surgical control and four to receive parenteral LE or saline infusion through jugular vein catheterization: SMOF (mixture of 30% medium-chain triglycerides, 30% soybean, 25% olive and 15% fish oils); MCT/LCT (physical mixture of 50% medium-chain triglycerides and 50% soybean oil); MCT/LCT/FO (80% MCT/LCT supplemented with 20% FO) and SS (saline). In the 5th experimental day and after intravenous colloidal carbon injection, blood and tissue (liver, lung and spleen) samples were collected and immunological analyses were performed.

RESULTS: LE didn't influence neutrophil chemotaxis. SMOF didn't influence phagocytosis (p>0.05) while MCT/LCT and MCT/LCT/FO LE increased the number of liver and lung resident macrophages that had engaged in phagocytosis compared with CO-NS and SS (p<0.05). Only MCT/LCT/FO increased the number of spleen resident macrophages that had engaged in phagocytosis (p<0.05).

CONCLUSIONS: LE, independently of composition, had no influence on neutrophils' chemotaxis, but showed different effect on phagocytosis by macrophages. SMOF LE had neutral effect while fish oil LE enriched with MCT/LCT LE increased resident-macrophages' phagocytosis.