In vitro 25-hydroxycholecalciferol treatment of lipopolysaccharide-stimulated chicken macrophages increases nitric oxide production and mRNA of interleukin- 1beta and 10

25-hydroxycholecalciferol (25(OH)D) is an intermediate metabolite during the biosynthesis of active vitamin D. In vitro studies were conducted in chicken monocytes and a chicken macrophage cell line (HD11) to study the effects of supplementing with 25(OH)D on nitrite production and mRNA amounts of interleukin (IL)-1β, IL-10, 1α-hydroxylase and 24-hydroxylase post- lipopolysaccharide (LPS) challenge. Supplementing HD11 cells and monocytes with 25(OH)D in the presence of LPS increased nitrite production by approximately 3-fold and 5-fold, respectively, compared to the LPS group. There was a linear increase in nitrite production by HD11 cells when treated with increasing doses of 25(OH)D. At 48 h post-LPS treatment, HD11 cells treated with either 25(OH)D or 1,25-dihydroxycholecalciferol(1,25(OH)2D) in the presence of LPS had higher amounts of IL-1β mRNA compared to the LPS group or the group treated with LPS and cholecalciferol (Chol). At 48 h, HD11 cells treated with 25(OH)D and stimulated with LPS had higher amounts of IL-10 mRNA compared to the LPS group or the groups treated with LPS and Chol or 1,25(OH)2D. At 48 h post-LPS treatment, HD11 cells treated with either 25(OH)D or 1,25(OH)2D and stimulated with LPS had higher amounts of 1α-hydroxylase and 24-hydroxylase mRNA compared to the group treated with LPS and Chol. In summary, a 25(OH)D treatment increased nitrite production and mRNA amounts of IL-1β, IL-10, 1α-hydroxylase and 24-hydroxylase in HD11 cells following LPS stimulation.