Fluoxetin suppresses tau phosphorylation and modulates the interaction between tau and tubulin in the hippocampus of CUMS rats

Depression is considered a crucial psychiatric disease correlated with neuronal-dysfunctions induced by stress-stimuli. This study aimed to investigate effect of Fluoxetine (FL) on chronic unpredictable mild stress (CUMS) and explore the associated mechanisms. CUMS rat model was established by treating with lots of stresses. CUMS rats were administered FL, SB216763 (SB), Wortmannin (WT) alone or in combination. CUMS rats were administered 1 % sugar water to conduct sugar water consumption experiment. Acet-Tub, Tyr-Tub, tau46, p-tau-Ser199/202, p-tau-Ser396, p-tau-Ser231, expression was examined using immunohistochemical assay and western blotassay. Interaction between tau and tubulin was evaluated with immunoprecipitation assay. Double immunohistochemical assay was used to identify interaction between Nestin and Tau. The results indicated that FL treatment only increased sugar consumption of CUMS rats (P < 0.05), but also strengthened effects of SB and WT. FL significantly treatment decreased tau phosphorylation (p-tau) in hippocampal tissues of rats compared to those of rats in CUMS group (P < 0.05). FL treatment markedly decreased Acet-Tub and increased Tyr-Tub expression in hippocampal tissues of rats compared to those of rats in CUMS group (P < 0.05). The effects of FL treatment on p-tau down-regulation and tubulin modulation in hippocampal tissues were independent from PI3K and GSK-3 signaling pathways. FL treatment could also enhance proliferation and total tau of newborn neurons of CUMS rats. FL treatment strengthened interaction between tau and botulin in hippocampal tissues of CUMS rats. In conclusion, Fluoxetin suppressed phosphorylation of tau and modulated the interaction between tau and tubulin in hippocampus of adult CUMS rats.