This study investigates the therapeutic effectiveness of intranasal dantrolene nanoparticles pretreatment to inhibit lipopolysaccharide (LPS)-induced pathological inflammation and synapse destruction and depressive and anxiety behavior in mice. Both wild-type (WT) B6SJLF1/J and 5XFAD adult mice (5-10 months old) were pretreated with intranasal dantrolene nanoparticles (dantrolene: 5mg/kg), daily, Monday to Friday, 5 days per week, for 4 weeks. Then, mice were treated with intraperitoneal injection of LPS (5mg/kg) for one time. Behavioral tests for depression, anxiety and side effects were performed 24 hours after a one-time LPS injection. Biomarkers for pyroptosis-related inflammation cytokines (IL-1β and IL-18) in blood and brains were measured using enzyme-linked immunosorbent assay (ELISA) and immunoblotting, respectively. The changes of primary proteins activation inflammatory pyroptosis (NLRP3: NLR family pyrin domain containing 3, Caspase-1, N-GSDMD: N terminal protein gasdermin D) and synapse proteins (PSD-95 and synpatin-1) in brains were measured using immunoblotting. Intranasal dantrolene nanoparticles robustly inhibited LPS-induced depression and anxiety behavior in both WT and 5XFAD mice, without obvious side effects. Intranasal dantrolene nanoparticles significantly inhibited LPS-induced pathological elevation of IL-1β and IL-18 in the blood and synapse loss in the brain. Intranasal dantrolene nanoparticles trended to inhibit LPS-induced elevation of IL1β and IL-18 and the pyroptosis activation proteins in the brain in both type of mice. In conclusion, intranasal dantrolene nanoparticles demonstrated neuroprotection against inflammation mediated depression and anxiety behaviors and should be studied furthermore as a future effective drug treatment of major depression disorder or anxiety psychiatric disorder, especially in AD patients.
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