Aerobic exercise improves memory and prevents cognitive deficits of relevance to schizophrenia in an animal model

Background Cognitive impairment associated with schizophrenia (CIAS)
greatly reduces patients’ functionality, and remains an unmet clinical
need. The sub-chronic phencyclidine (scPCP) rat model is commonly
employed in studying CIAS. We have shown that voluntary exercise
reverses impairments in novel object recognition (NOR), induced by
scPCP. However, there has not been a longitudinal study investigating
the potential protective effects of exercise in a model of CIAS. Aim To
investigate the pro-cognitive and protective effects of exercise on CIAS
using the translational NOR and attentional set-shifting tasks (ASST).
Methods Female Lister Hooded rats were either exercised (wheelrunning:
1 hr/day, 5 days/week for 6 weeks, n=20) or not (n=20) and
then tested in a natural-forgetting NOR test. Rats in each group were
then administered either PCP (2 mg/kg intra-peritoneally, i.p.) or saline
solution (1 ml/kg i.p.) for 7 days, followed by 7 days washout. Three
NOR tests were conducted immediately, and 2 and 9 weeks after
washout, and a natural-forgetting NOR test carried out again 8 weeks
post-washout. Rats were trained and tested in ASST from week 6 to
week 10 post-washout. Results Non-exercised rats displayed a deficit in
both of the natural-forgetting NOR tests, whereas exercised rats did not.
The scPCP exercise group did not show the expected deficit in NOR at
any time-point, and had a significantly ameliorated deficit in the ASST
compared to the scPCP control group. Conclusion Voluntary exercise has
long-lasting pro-cognitive and protective effects in two cognitive
domains. Exercise improves cognition and could provide protection against CIAS.