Effect of a Short-Term Infusion with Soybean Oil-Based Lipid Emulsion on Phagocytosis of Canine Peripheral Blood Polymorphonuclear Neutrophilic Leukocytes
The objective of this study was to examine the effect of a short-term infusion with soybean oil (SO)-based lipid emulsion (LE) on functions of canine peripheral blood polymorphonuclear neutrophilic leukocytes (PMNs). Twenty four healthy Beagles were randomly assigned to receive 4 treatments (6 dogs per treatment). Treatment A consisted of IV infusion of 0.9% NaCl solution (control treatment). Treatments B, C, and D consisted of IV infusion of SO-based LE (Intralipose 20%) that supplied 40, 100, and 200% of daily energy requirements, respectively. All treatments were infused for 2 hours. To evaluate PMNs function, blood samples were collected before IV infusion of SO-based LE, immediately after infusion, and 24 hours after completion of the infusion. The phagocytic capacity and oxidative burst activity (OBA) were analyzed simultaneously by use of flow cytometry, and the actin polymerization was assayed by use of flow cytometry and confocal microscopy. The Cdc42 activation levels in phorbol myristate acetate-treated PMNs were determined by affinity precipitation using Cdc42 activation assay kit.
All treatments had no significant effect on the phagocytic capacity of PMNs. However, the values for OBA and actin polymerization were reduced in only treatment D and restored to normal values 24 hours after infusion. The activation of Cdc42 was also inhibited by treatment D. In conclusion, these results suggest that the short-term infusion with a supraphysiologic dose of SO-based LE can decrease the immune functions of canine PMNs, but infusions with clinically relevant doses of SO-based LE may not trigger any significant inhibitory effects.