Acute and protracted changes in the liver of Syrian hamsters induced by a single dose of aflatoxin B1. Observations on pathological effects of the solvent (dimethylformamide).

Male Syrian hamsters, 8-10 weeks of age, were treated with a single intraperitoneal injection of crystalline aflatoxin B1 in solution of N -N -Dimethylformamide (DMF). The concentrations of aflatoxin were adjusted to the smallest controllable amount of solvent in relation to the size of the animal (0-5 or 1-0 ml/kg). Treatment with, respectively, 5-0 or 2-5 mg/kg aflatoxin in 1-0 ml/kg DMF was lethal to most animals within one week. However, reduction of the solvent to 0-5 ml/kg, while not eliminating the mortality entirely during the first week, made possible observation of the survivors up to 28 days. Hamsters appear to be more susceptible to DMF poisoning than other species, like rat, guinea-pig and rabbit in which this solvent was used by investigators on the biological effects of aflatoxin. Either dose given of DMF alone was lethal for several animals during the first week of observation and sufficient to produce histological lesions in the liver which were characteristic and clearly different from those induced by aflatoxin during the same period. DMF alone caused centrilobular necrosis which was accompanied by haemosiderosis of liver structures. With a aflatoxin, in addition, periportal and midzonal necrosis of the liver was present. Aflatoxin B1 and B1 and DMF both induce haemorrhagic tendency probably involvement in the coagulation process of the blood. It cannot be decided, however, at present whether this is the result of an indentical mechanism.