Toxic effects of atrazine on immune function in BALB/c mice

This study was aimed to evaluate the toxic effects of different concentrations (23, 90, 360 mg/kg BW) of atrazine (ATZ) on immune function in BALB/c mice. Some parameters of general immunotoxicity, humoral immunity, cellular immunity, and non-specific immunity were tested. The studies showed that the high-dose ATZ induced a significant reduction in the final body weight of mice, the absolute and relative weights of spleen, the counts of white blood cell (WBC), lymphocyte (LYM), monocyte (MON), and the number of splenocyte. An increase in the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and cholesterol (CHO) in the high-dose ATZ group was observed. Pathological examination showed that the medium- and high-doses of ATZ caused atrophy and destruction of thymus, spleen, and hepatorenal toxicity. The serum interleukin-5(IL-5) level of mice and the number of plaque-forming cell (PFC) in spleen cells in the high-dose ATZ group decreased significantly while there was a significant increase of the serum immunoglobulin G (IgG) in the high-dose ATZ group when compared to the negative control group. In the high-dose ATZ group, the proliferation ability of T and B lymphocytes as well as the delayed-type hypersensitivity (DTH) response were significantly decreased. The low-dose ATZ (23 mg/kg BW) caused a significant decrease in the number of WBC and neutrophil (NEUT), as well as the proportion of polychromatic and normoblast. In summary, we thought the low-dose ATZ has a slight effect on the immune system; it can be preliminarily concluded that the lowest observed adverse effect level (LOAEL) of atrazine is 23 mg/kg BW in mice. Atrazine can cause immunotoxicity mainly through cellular and humoral immunity pathways.