Omega-3 fatty acids are able to modulate the painful symptoms associated to cyclophosphamide-induced-hemorrhagic cystitis in mice

This study investigated the effects of the long-term dietary fish oil supplementation or the acute administration of the omega-3 fatty acid docosahexaenoic acid (DHA) in the mouse hemorrhagic cystitis (HC) induced by the anticancer drug cyclophosphamide (CYP). HC was induced in mice by a single CYP injection (300 mg/kg ip). Animals received four different diets containing 10% and 20% of corn or fish oil, during 21 days. Separated groups received DHA by ip (1 μmol/kg) or intrathecal (i.t.; 10 μg/site) routes, 1 h or 15 min before CYP. The behavioral tests (spontaneous nociception and mechanical allodynia) were carried out from 1 h to 6 h following CYP injection. Bladder inflammatory changes, blood cell counts and serum cytokines were evaluated after euthanasia (at 6 h). Immunohistochemistry analysis was performed for assessing spinal astrocyte and microglia activation or GPR40/FFAR1 expression. Either fish oil supplementation or DHA treatment (ip and i.t.) markedly prevented visceral pain, without affecting CYP-evoked bladder inflammatory changes. Moreover, systemic DHA significantly prevented the neutrophilia/lymphopenia caused by CYP, whereas this fatty acid did not significantly affect serum cytokines. DHA also modulated the spinal astrocyte activation and the GPR40/FFAR1 expression. The supplementation with fish oil enriched in omega-3 fatty acids or parenteral DHA might be interesting nutritional approaches for cancer patients under chemotherapy schemes with CYP.