New co-drugs of O-demethylvenlafaxine and NSAIDs exert antidepressant effects by alleviating inflammation, oxidative stress, and increasing neurotransmitter.

Depression and anxiety disorders are highly comorbid, yet their complex pathogenesis often limits the efficacy of monotherapy. Growing evidence implicates neuroinflammation in their pathogenesis. Co-drugs that linked two active molecules into a single compound and released the drugs after administration, which offering improved efficacy and tolerability than individual drug mixtures or monotherapy. In this work, five new co-drugs ODV-NSAIDs were synthesized from O-desmethylvenlafaxine (ODV) with non-steroidal anti-inflammatory drugs (NSAIDs) to achieve synergistic antidepression and anxiolytic effects. In vitro stability studies exhibited that these co-drugs can be metabolized into two single drugs within 60 min in simulated intestinal fluid. In both acute and chronic LPS-induced models, co-drug ODV-NAP significantly ameliorated depressive-like behaviors, evidenced by increased sucrose preference, reduced immobility in the tail suspension test (TST) and forced swim test (FST), and enhanced locomotion in the open field test (OFT). Furthermore, ODV-NAP decreased brain levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and malondialdehyde (MDA), while elevating serotonin (5-HT), norepinephrine (NE), and superoxide dismutase (SOD) activity. Nissl staining confirmed ODV-NAP significantly attenuated hippocampal neuronal damage. Moreover, western blotting revealed ODV-NAP inhibited the TLR4/NF-κB signaling pathway and upregulated BDNF and p-TrkB protein expression. ODV-NAP also inhibited LPS-induced p65 nuclear translocation in BV-2 microglia in vitro, and caused no toxicity in histology. Thus, co-drug ODV-NAP represented a promising novel candidate for treating depression and anxiety.