The effects of the anti-cancer drugs, methotrexate and 5-fluorouracil, on cognitive function in mice.

There is evidence that standard-dose chemotherapy may impact cognitive function in cancer patients. The present study evaluated the effects of a combination of two anti-cancer drugs, methotrexate (37.5 mg/kg) and 5-fluorouracil (5FU, 75 mg/kg) on cognitive function in a mouse model. Drug-induced deficits were observed in adult BALB/C mice on tests of spatial memory, non-matching-to-sample (NMTS) learning and in a delayed-NMTS test of non-spatial memory. There were no group differences on tests of cued memory or discrimination learning. Performance-related variables were ruled out as possible explanations of the observed impairments. The impaired performance of the drug group, which was consistent with cognitive deficits observed in human cancer patients treated with similar types of chemotherapy, was attributed to functional changes in specific brain regions, including the frontal lobes and hippocampus.