In Vivo Immunologic Alterations by a Food Antioxidant Butylated Hydroxyanisole (BHA) in Male Swiss-Webster Mice

Butylated hydroxyanisole (BHA) is considered to be an anticarcinogenic substance in experimental animals, and has been shown to have immunosuppressive activity in vitro. Male Swiss-Webster mice were fed semisynthetic powder diets containing 0.02% or 0.2% BHA. Splenic lymphocytes from mice exposed for 9 or 30 days were cultured in vitro with or without mitogens, namely phytohemagglutinin (PHA), pokeweed mitogen (PWM) or bacterial lipopolysaccharide (LPS). At the level of 0.02% BHA in the diet, ³H-thymidine uptake by PHA-stimulated splenic cells from the 9-day feeding group was elevated. The uptake of ³H-thymidine of the splenic cells of the 30-day treatment was reduced with all mitogens used at both BHA levels, but not significantly. After a 23-day exposure, splenic lymphocytes from animals inoculated with sheep erythrocytes were tested for plaque formation. No significant differences were apparent among treatment groups. Delayed hypersensitivity in mice, as measured by the incorporation of ³H-thymidine after repeated sensitization and challenge with oxazolone, was not significantly affected by a 28-day exposure at either level of BHA. Significant differences of organ weights were obtained; however, these differences may not have been associated with the effect of BHA on the immune system. The effects of the low (0.02%) and high (0.2%) doses on BHA on immunomodulation in mice were not clearly shown to be either suppressive or stimulative.