14 EFFECT OF PORCINE SEMINAL PLASMA AND EGG YOLK ON CHEMOTAXIS AND PHAGOCYTOSIS OF NEUTROPHILS DERIVED FROM PERIPHERAL BLOOD OF PIGS AND COWS

Abstract

The aim of this study was to determine the effects of porcine seminal plasma (0 to 20%, vol/vol) and egg yolk (0 to 20%, vol/vol) on chemotaxis and phagocytosis of porcine and bovine polymorphonuclear neutrophil (PMN) in vitro. Chemotaxis was determined using a blind well chamber. The phagocytosis assay was performed according to (Matthijs et al. 2000 J. Reprod. Fertil. 120, 265–273) with modification in pigs and cows. The serum-stimulated chemotactic activity of PMN (porcine, 1126.1 ± 14.4 cells/mm² and bovine, 1067.1 ± 9.5 cells/mm²) was reduced (n = 4; P < 0.05) in the presence of 5% pig seminal plasma (pig, 1009.3 ± 12.4 cells/mm² and cow, 800.0 ± 17.3 cells/mm²). More than 5% (vol/vol) of pig seminal plasma significantly decreased the chemotaxis of PMN in pigs and cows. The presence of 1% and higher concentrations (vol/vol) of seminal plasma reduced (n = 4; P < 0.05) leukocyte phagocytosis in pigs (37.1 ± 1.4 v. 41.7 ± 1.0%) and cows (36.4 ± 1.6 v. 42.1 ± 1.1%) compared with controls, and higher concentrations decreased the phagocytotic activity of PMNs in a concentration-dependent manner (n = 4; P < 0.05). Interestingly, 20% egg yolk increased (n = 4; P < 0.05) chemotaxis of PMN in pigs (953.5 ± 11.6 v. 789.9 ± 13.1 cells/mm²) and cow (988.6 ± 14.6 v. 790.4 ± 19.4 cells/mm²) compared with controls. The egg yolk increased (n = 4; P < 0.05) phagocytosis ability of porcine PMN (35.3 ± 1.6 v. 24.9 ± 2.4%) compared with the control. However, 20% egg yolk did not affect phagocytotic ability of PMN in cows (15.1 ± 1.6 v. 15.8 ± 1.0%). These results demonstrated that porcine seminal plasma, regardless of whether the species was pigs or cows, reduced chemotactic and phagocytotic activities of PMN. However, egg yolk significantly increased chemotactic activity of PMN in pigs and cows, while the egg yolk increased phagocytosis of PMN in pigs, but not in cows. In addition, porcine seminal plasma and caffeine reduced the egg yolk-induced increase in chemotactic and phagocytotic activities of PMN in both species.