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.