Ginsenoside Rg1 alleviates PCPA-induced insomnia by inhibiting NLRP3 inflammasome activation and pyroptosis through the Nrf2/HO-1 pathway in mice

OBJECTIVES: This study aims to investigate the neuroprotective effects of Ginsenoside Rg1 in alleviating P-chlorophenylalanine (PCPA)-induced insomnia and explore its underlying mechanisms involving the inhibition of NOD-Like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome activation and pyroptosis through the Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2)/Heme Oxygenase-1 (HO-1) pathway in mice. METHODS: Sprague-Dawley rats were randomly divided into five groups: control, sleep deprivation (SD, PCPA-induced insomnia), and three treatment groups receiving different doses of Ginsenoside Rg1 (low, medium, and high). Behavioral assessments included the Pentobarbital Sodium-Induced Sleep Test (PIST), Sucrose Preference Test (SPT), and Morris Water Maze (MWM). Histopathological and immunofluorescence evaluations of hippocampal tissues were performed. Enzyme-Linked Immunosorbent Assay (ELISA) was used to measure neurotransmitter levels (5-Hydroxytryptamine [5-HT], 5-Hydroxytryptophan [5-HTP], Gamma-aminobutyric acid [GABA], glutamate [GLU]) and pro-inflammatory cytokines (Tumor Necrosis Factor Alpha [TNF-α], Interleukin-6 [IL-6], Interleukin-1 beta [IL-1β], Interleukin-8 [IL-8]). In vitro, corticosterone-induced neurotoxicity in HT22 hippocampal cells was assessed, and the role of the Nrf2/HO-1 pathway was examined through molecular docking, gene silencing, and Western blot. RESULTS: Ginsenoside Rg1 treatment significantly improved PCPA-induced insomnia symptoms in a dose-dependent manner, as evidenced by reduced sleep latency, increased sleep duration, restored sucrose preference, and improved spatial memory. Histopathological analysis revealed that Ginsenoside Rg1 mitigated neuronal damage and astrocytic activation. Neurotransmitter imbalances were corrected, and inflammation was alleviated, as reflected by reductions in pro-inflammatory cytokines and increased interleukin-10 (IL-10) levels. Mechanistically, Ginsenoside Rg1 inhibited NLRP3 inflammasome activation, pyroptosis, and reduced IL-1β and IL-8 levels in both in vivo and in vitro models. The activation of the Nrf2/HO-1 pathway was further confirmed by molecular docking, immunofluorescence, and Western blot, demonstrating that Nrf2 activation was critical for the anti-inflammatory effects of Ginsenoside Rg1. CONCLUSION: Ginsenoside Rg1 effectively alleviates PCPA-induced insomnia by inhibiting NLRP3 inflammasome activation and pyroptosis, with its neuroprotective effects mediated through the activation of the Nrf2/HO-1 pathway. These findings suggest Ginsenoside Rg1 as a potential therapeutic agent for insomnia and related neuroinflammatory conditions.