“Introduction: Nicotine pouches are rapidly increasing in popularity, yet their long-term neurological consequences remain poorly understood. Emerging evidence suggests nicotine may influence seizure susceptibility and neuroimmune signaling, while cannabidiol (CBD) has demonstrated neuroprotective and anti-inflammatory effects. This study investigated the time-dependent impact of acute versus chronic oral nicotine exposure on seizure vulnerability, neuroinflammation, and glymphatic function, and evaluated whether inhaled CBD can reverse these pathological changes.
Methods: Mice were exposed to acute or 7-day chronic nicotine pouch prior to kainic acid-induced seizures. Seizure severity was scored using the Racine scale. Neuroinflammatory markers (IL-6, HMGB1), neuronal activation markers (BDNF, c-FOS), and AQP4 expression were quantified via flow cytometry, immunofluorescence, and Western blotting. Glymphatic function was assessed using cisterna magna injection of rhodamine dextran tracers. An ex vivo IL-6 modulation assay evaluated nicotine-induced cytokine production and CBD-mediated suppression, with or without IL-6 receptor blockade.
Results: Acute nicotine transiently reduced seizure severity, whereas chronic exposure significantly exacerbated seizures, elevated IL-6, HMGB1, BDNF, and c-FOS, and markedly downregulated AQP4. CSF tracer studies confirmed impaired glymphatic influx following chronic nicotine exposure. CBD inhalation effectively reversed seizure severity restored AQP4 expression, normalized IL-6 and HMGB1 levels, and reduced c-FOS protein expression. The IL-6R blockade assay showed that nicotine induces IL-6 production in brain-derived immune cells, while CBD suppresses this response upstream of IL-6 signaling.
Conclusions: Chronic nicotine pouch exposure promotes seizure susceptibility through converging neuroimmune and glymphatic disruptions. Inhaled CBD counteracts these effects, supporting its potential as a targeted therapeutic strategy for nicotine-associated neurological risk.”