Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is a substitute
urea herbicide widely used on agricultural crops with potential mutagenic, teratogenic, reproductive and carcinogenic effects. Nonetheless, its toxic potential on the immune system needs a detailed assessment. Thus, in order to evaluate the adverse effect of this
herbicide on lymphohematopoietic organs and macrophage activity, male Wistar rats were orally treated with
Diuron at 125, 1250 and 2500 ppm for 14, 28 or 90 days. General signs of toxicity were observed in
Diuron-treated groups (1250 and 2500 ppm), including reduced food intake and
body weight gain, as well as higher relative weights for spleen, kidneys and liver (28 and 90-day toxicity studies) and elevated serum levels of ALT,
albumin, total
protein,
creatinine and
urea (28-day toxicity study).
Diuron exposure caused a severe depletion of splenic white pulp compartments and cellularity, followed by a decreased number of CD4(+) T lymphocytes, increased extramedullary hematopoiesis and deposition of
hemosiderin in red pulp. Despite alteration in macrophage spreading, the macrophagic activity was not significantly affected by the
herbicide. Under these experimental conditions, the results suggest that
Diuron exerts systemic and target-organ toxicity, mainly at higher concentration.