Immunobiological effects of fumonisin B1 in experimental subchronic mycotoxicoses in rats.

Fumonisin B1 (FB1), the principal secondary metabolite produced by the fungus Fusarium verticillioides (Gibberella fujikuroi mating population A), is a potent toxin that can be found in fungus-contaminated corn and corn-based food products. We have investigated the immunobiological effects of subchronic dietary exposure to FB1 in male Wistar rats. Animals were fed with diets containing 0 (control) or 100 ppm of FB1 for 12 weeks. The total FB1 intake on day 90 was 810 mg/kg of body weight. Food consumption, body weight, and body weight gain on day 90 were reduced in animals exposed to FB1. Histopathologic changes consisted of histiocytic perivascular infiltrate and an increased number of Kupffer cells in the liver, necrosis and apoptosis of tubular epithelial cells in the kidney, and increased mitotic figures and lymphocytic infiltrate in the small intestine. Serum enzyme alkaline phosphatase was significantly elevated in rats fed FB1, while triglyceride levels decreased compared to controls. Treatment with FB1 in vivo or in vitro did not have a significant effect on mitogen-induced proliferation of spleen mononuclear cells. However, increased levels of interleukin-4 (IL-4) and decreased levels of IL-10 were released by these cells in culture compared to controls. FB1 in vivo or in vitro decreased the hydrogen peroxide (H(2)O(2)) released by peritoneal macrophages, while no changes in levels of superoxide anion produced by total peritoneal cells were detected. The results from the present work demonstrate that subchronic FB1 intake could affect the small intestine and alter the interleukin profile and some main functions of macrophages in antitumor activity.