Effects of vitamins A and E on superoxide production and intracellular signaling of neutrophils in Holstein calves.

The effects of vitamin A and vitamin E treatment on superoxide (O2-) production of neutrophils and their intracellular signaling, including intracellular Ca2+, protein kinase C (PKC), and tyrosine kinase (TK), were examined in Holstein calves. After treatment with vitamin A, heat-aggregated IgG (H-agg.IgG)-induced O2- production in neutrophils ranged from 3.7+/-0.4 to 4.3+/-0.9 nmol (mean +/- SD), and it was significantly (P<0.05) higher than that in the control calves. Opsonized zymosan (OPZ)-induced O2- production was similar with that of control calves. Intracellular signaling of neutrophils in vitamin A-treated calves was enhanced compared with that of control calves when stimulated with H-agg. IgG, but not with OPZ. After treatment with vitamin E, H-agg.IgG- and OPZ-induced O2- production of neutrophils ranged from 4.2+/-0.8 nmol to 5.4+/-0.5 nmol and from 7.8+/-0.6 nmol to 8.1+/-0.4 nmol (mean +/- SD), respectively, and they were significantly (P<0.05) higher than those in control calves. Intracellular signaling was also enhanced compared with that of control calves. These results suggested that the effects of vitamin A and E treatment on O2- production were correlated to changes in intracellular signaling of neutrophils in Holstein calves.