Subchronic administration of Trichilia catigua ethyl-acetate fraction promotes antidepressant-like effects and increases hippocampal cell proliferation in mice

Abstract Ethnopharmacological relevance Trichilia catigua preparations have been popularly used in Brazil as a tonic for the treatment of fatigue, stress, impotence, and memory deficits. We recently demonstrated an antidepressant-like effect of acute administration of the Trichilia catigua ethyl-acetate fraction (EAF) in mice. The aim of the present study was to evaluate whether subchronic Trichilia catigua EAF administration maintains its antidepressant-like effects and whether these effects are related to hippocampal neurogenesis. Material and methods Trichilia catigua EAF (200 and 400 mg/kg) was orally administered to mice for 14 day. The animals were tested in the forced swim test (FST) or tail suspension test (TST). After behavioral testing, the animals received bromodeoxyuridine (BrdU; 200 mg/kg, i.p.) and were euthanized 24 h, 7 day, or 15 day later. The brains were assayed for BrdU and doublecortin (DCX) immunohistochemistry to detect cell proliferation/survival and neurogenesis, respectively. Results Subchronic administration of 400 mg/kg Trichilia catigua EAF promoted antidepressant-like effects in mice in both the FST and TST. The antidepressant-like effect was accompanied by an increase in cell proliferation in the dentate gyrus (DG) of the hippocampus 24 h after the treatments were discontinued. This proliferative effect, however, did not influence cell survival or neurogenesis because no change in the number of BrdU- or DCX-positive cells was detected 7 or 15 day after the last EAF administration compared with controls. Conclusions Trichilia catigua EAF produced antidepressant-like effects and induced hippocampal cell proliferation in mice. The results contribute information on the pharmacological and molecular mechanisms involved in the antidepressant-like effect of Trichilia catigua EAF.