Long-term cognitive dysfunction in the rat following docetaxel treatment is ameliorated by the phosphodiesterase-4 inhibitor, rolipram

Abstract

Clinical studies report evidence of long-term cognitive and other deficits following adjunctive chemotherapy treatment, which is often termed “chemobrain” or “chemo-fog”. The neurological bases of these impairments are poorly understood. Here, we hypothesize that systemic chemotherapy treatment causes long-term neurobehavioral deficits, and that these deficits are reversed by manipulation of cAMP by the PDE4 inhibitor, rolipram.Male han Wistar rats were treated with docetaxel (an adjunctive chemotherapeutic agent (1mg/kg i.v.)) or control solution (ethanol/Tween 20/0.9% Saline – 5/5/90) once per week for 4 weeks. They were allowed to recover for 4 weeks, administration of rolipram (0.5mg/kg po) or vehicle (maple syrup) then began and continued daily for 4 weeks. At the end of the treatment regime animals were tested for spatial and recognition memory deficits with the object exploration task and for depressive- and anxiety-like behavior in the forced swim test (FST) and open field exploration.We report docetaxel treatment impaired spatial memory but not object recognition memory, compared to control rats. Docetaxel-treated rats also spent significantly more time immobile than controls in the FST. Chronic rolipram treatment attenuated all of these docetaxel-associated changes, recovering spatial memory and reducing immobility. In conclusion, docetaxel-treated rats exhibit alterations in spatial memory and depressive-like behavior, which are reversed following chronic rolipram administration. These results detect long-term cognitive and mood changes following docetaxel treatment and identify PDE4 inhibition as a target treatment of neuropsychological changes associated with “chemobrain”.