Effects of vitamin D3 and vitamin E on prednisolone-induced alterations of phagocyte function

To evaluate the effectiveness of vitamin D3 and its combined action with vitamin E in the correction of the impairments of phagocyte function caused by chronic glucocorticoid administration.

Phagocytic activity was assessed by the ability of peripheral blood neutrophils and monocytes to capture FITC-labeled Escherichia coli using flow cytometry. Metabolic activity of neutrophils was measured cytochemically as nitro blue tetrazolium (NBT) reduction test. Intracellular reactive oxygen species (ROS) were detected by 2',7'-dichlorofluorescein fluorescence.

Prednisolone administration (5 mg/kg b.w., 30 days) was accompanied by vitamin D3 deficiency and decompensation of phagocyte function associated with antimicrobial activity (decrease in NBT reduction rate, ROS formation and phagocytic activity). Vitamin D3 co-administration with prednisolone and, to a greater extent, its combination with α-tocopherol (100 IU and 0.5 mg/rat, 30 days respectively) partially restored phagocyte function.

These data suggest that vitamin D3 and α-tocopherol can prevent immunosuppressive effects of prednisolone through elevating the efficacy of oxygen-dependent mechanisms of phagocytosis and increasing the functional activity of phagocytic cells.