2.13. LPS-induced neuroinflammatory model of mice

The LPS-induced neuroinflammatory model in mice has been broadly validated [51,52]. The mice were randomly divided into four groups (12 mice per group) and administered either vehicle [0.2% (w/v) poloxamer 188 (BASF, Ludwigshafen, Germany) solution] or DBZ (5, 20 mg·kg⁻¹ in the vehicle) once a day (9:00 a.m.) by intraperitoneal injections for four consecutive days, respectively. On the fourth day, mice were intraperitoneally injected with LPS (0.33 mg·kg⁻¹ in saline) or normal saline, 2 h after injection of DBZ or vehicle. The dosage of LPS was selected because it elicits a proinflammatory cytokine response in the brain resulting in mild transient sickness behavior in adult mice [47,48]. The randomized treatment administrations were performed to simultaneously assess the effect of different treatments and avoid time-variable environmental influences. The doses of DBZ used in the experiments were based on a pilot preclinical study and the Good Laboratory Practice toxicology studies in mice by intravenously injection (LD50 = 460.700 mg·kg⁻¹ ± 26.107 mg·kg⁻¹) by National Beijing Centre for Drug Safety Evaluation and Research. At 24 h after LPS injection, mice were euthanized in a CO₂ chamber. The whole brains were carefully removed and the cerebral cortex was isolated for further studies.