Immunotoxicological investigations on rats treated subacutely with dimethoate, As3+and Hg2+ in combination

Effects of combined exposure with dimethoate (DM), HgCl2(Hg),andNaAsO2 (As)wereinvestigatedfollowinga28-day oral exposure in male Wistar rats. In preliminary experiments, the LOEL (Lowest Observed Effect Level) and NOEL (Non Observed Effect Level) doses of the substances were determined using the same experimental system [determination of body weight gain, organ weights of brain, thymus, heart, lung, kidneys, adrenals, spleen, testicles, popliteal lymph node, white blood cell (WBC) and red blood cell (RBC) count, haematocrit (Ht), mean cell volume (MCV) of RBCs, cell content of the femoral bone marrow, IgM-plaque forming cell (PFC) content of the spleen, delayed type hypersensitivity (DTH) reaction] and animal strain. In the combination studies, LOEL dose of DM (28.2 mg/kg) was combinedwithNOELdosesoftheheavymetals(HgCl2 =0.40 mg/kg, NaAsO2 =3.33 mg/kg), and vice versa (DM=7.04 mg/kg, HgCl2 =3.20 mg/kg, NaAsO2 =13.3 mg/kg). In the DM–Hg combinations, significant alterations were found versus the correspon...