title: The effects of chemotherapy on cognitive function in a mouse model: a prospective study.
abstract: OBJECTIVE
  Clinical studies indicate that up to 70% of patients with cancer who receive chemotherapy experience cognitive impairment. The present study used a prospective longitudinal design to assess short- and long-term effects of commonly used anticancer drugs on cognitive performance in a mouse model.
  
  
  METHODS
  Normal mice received three weekly injections of a combination of methotrexate + 5-fluorouracil (CHEMO group) or an equal volume of saline (SAL group). Cognitive tests, measuring different aspects of learning and memory, were administered before treatment, immediately after treatment, and three months later. Structural MRI scanning was conducted at each stage of cognitive testing.
  
  
  RESULTS
  The CHEMO group exhibited deficits on cognitive tasks acquired pretreatment [spatial memory, nonmatching-to-sample (NMTS) learning, and delayed NMTS], as well as impaired new learning on two tasks (conditional associative learning, discrimination learning) introduced posttreatment. Consistent with clinical evidence, cognitive deficits were pronounced on tests that are sensitive to hippocampal and frontal lobe dysfunction, but the CHEMO group's poor performance on the discrimination learning problem suggests that impairment is more widespread than previously thought. Cognitive deficits persisted for at least three months after treatment but some recovery was noted, particularly on tests thought to be under frontal lobe control. The MRI tests did not detect brain changes that could be attributed to treatment.
  
  
  CONCLUSIONS
  Chemotherapeutic agents can have adverse effects on information acquired pretreatment as well as new learning and memory and, despite some recovery, impairment is long lasting.
authors.affiliation: Rotman Research Institute, Baycrest Centre, Ontario, Canada. gwinocur@rotman-baycrest.on.ca
authors.forename: Gordon
authors.initials: G
authors.lastname: Winocur
authors.forename: Mark
authors.initials: M
authors.lastname: Henkelman
authors.forename: J Martin
authors.initials: JM
authors.lastname: Wojtowicz
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhang
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Binns
authors.forename: Ian F
authors.initials: IF
authors.lastname: Tannock
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects*; D003071:Cognition / Q000187:drug effects*; D004195:Disease Models, Animal; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects; D007858:Learning / Q000187:drug effects; D008137:Longitudinal Studies; D008568:Memory / Q000187:drug effects; D008727:Methotrexate / Q000009:adverse effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009483:Neuropsychological Tests; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D005472:Fluorouracil; D008727:Methotrexate