RESUMO
The purpose of this study was to evaluate the effect of meloxicam (MEL) on selected immune parameters of bovine CD25highCD4+, CD25lowCD4+, and CD25-CD4+ cells. Peripheral blood mononuclear cells (PBMCs) collected from 12-month-old heifers were treated with MEL at a concentration corresponding to the serum level of this medication following administration at the recommended dose (MEL 5 x 10(-6) M) and at a concentration 10 times lower (MEL 5 x 10(-7) M). After 12 and 24 h of incubation with the drug, the percentage of CD25highCD4+ cells decreased; however, this disturbance was quickly reversed. Furthermore, the absolute number of CD25highCD4+ cells in the PBMC populations treated with MEL 5 x 10(-6) M for 48 and 168 h was increased. Prolonged (168 h) exposure to the drug increased the percentage of Foxp3+ cells in the CD25highCD4+ cell subpopulation. The higher dose of MEL was found to significantly increase the percentage of IFN-gamma+ cells among the CD25-CD4+ cells. These results indicated that MEL does not exert an immunosuppressive effect by depleting CD4+ cells and suppression of IFN-gamma+ production by these cells. Furthermore, IL-10 and TGF-beta production was not changed following exposure to MEL.