Abstract: Objective: To investigate the alleviating effects and underlying mechanisms of eicosapentaenoic acid-enriched phosphatidylserine (EPA-PS) on olanzapine (OLZ)-induced intestinal injury in mice. Methods: Thirty-two female C57BL/6J mice were randomly divided into a control group (CON), a model group (MOD), a low-dose EPA-PS group (L-EPA-PS, 50 mg/kg), and a high-dose EPA-PS group (H-EPA-PS, 100 mg/kg). To induce intestinal injury, all mice except those in the CON group were orally administered with OLZ at a dose of 8 mg/kg for 42 consecutive days. Meanwhile, mice in the L-EPA-PS and H-EPA-PS groups received the corresponding doses of EPA-PS. At the end of the experiment, inflammatory cytokine levels, oxidative stress indicators, and tight junction protein expression in jejunal tissues were measured. Histopathological analysis was performed, and untargeted metabolomics and microbiota diversity analyses were conducted on intestinal contents. Results: Compared with the MOD group, EPA-PS intervention significantly reduced the levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α) in mice (P < 0.05). EPA-PS also significantly increased the level of secretory immunoglobulin A (sIgA) and the activities of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase (P < 0.05), while significantly decreasing malondialdehyde (MDA) levels (P < 0.05). Histopathological and immunofluorescence analyses showed that EPA-PS improved jejunal tissue structure and significantly up-regulated the expression of related tight junction proteins (P < 0.05). Untargeted metabolomics analysis of intestinal contents indicated that EPA-PS alleviated OLZ-induced intestinal metabolic disturbances by regulating tryptophan, sphingolipid, and arachidonic acid metabolism. In addition, gut microbiota diversity analysis demonstrated that EPA-PS ameliorated OLZ-induced gut microbiota dysbiosis by modulating the abundance of Bacteroidota, norank_f__Muribaculaceae, Bifidobacterium, Faecalibaculum, Turicibacter, and Dubosiella. Conclusion: EPA-PS may alleviate OLZ-induced intestinal injury in mice, potentially through the regulation of inflammatory responses and oxidative stress, the modulation of gut microbiota structure, and the amelioration of intestinal metabolic disturbances

Key words: olanzapine; eicosapentaenoic acid-enriched phosphatidylserine; intestinal injury; metabolomics; gut microbiota