The effect of steroidal and non-steroidal anti-inflammatory drugs on the cellular immunity of calves with experimentally-induced local lung inflammation

We examined the effect of a single intravenous dose of flumetasone (SAID) and meloxicam (NSAID) treatment of calves with experimentally-induced localized lung inflammation on immunological and hematological variables such as total protein, gamma globulin, hemoglobin (Hb) concentrations, alkaline phosphatase activity, packed red cell volume (PCV), red blood cell (RBC) and white blood cell (WBC) counts. The influence of drug treatment on the phagocytic activity of WBC and bronchoalveolar lavage (BAL) cells and their ex vivo ability to produce interferon (IFN) and tumor necrosis factor (TNF) after induction with Newcastle disease virus (NDV), as well as on the development of PHA-induced skin delayed hypersensitivity reaction was also determined. Two days after the treatment of calves with experimentally-induced local lung inflammation with flumetasone (5 mg per calf), we observed a significant increase in WBC count, especially neutrophils, and a decrease in gamma globulin concentration, in the percent of blood phagocytic cells and their random migration. Flumetasone treatment also inhibited the development of skin delayed hypersensitivity reaction. In contrast, the treatment of calves with meloxicam (50 mg per calf) did not influence any hematological parameters or skin reactivity. Both drugs, flumetasone and meloxicam, influenced TNF production in ex vivo cultures of blood and BAL cells, inhibiting excessive TNF production induced by local lung inflammation. Contrary to TNF, the treatment of calves with meloxicam and flumetasone enhanced ex vivo IFN production in blood and BAL cells. Histological examination of lung tissue revealed that in control calves (those not treated with anti-inflammatory drugs) and in calves treated with flumetasone, symptoms of stromo-purulent inflammation of pulmonary tissue developed. However, in calves treated with meloxicam, only interstitial inflammation with a slight thickening of interalveolar septa and infiltration of lymphoid cells was observed. These results suggest that in this model of pneumonia, it is more appropriate to use a single dose of meloxicam, rather than flumetasone, to modulate lung inflammation.