Protective Role of CBD Against Nicotine Pouch-Induced Seizure Aggravation and Alterations in Brain Glymphatic...

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.

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 Aquaporin-4 (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.

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.

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.

This study provides the first evidence that chronic nicotine pouch exposure disrupts glymphatic function, amplifies neuroinflammation, and increases seizure susceptibility through an IL-6-centered neuroimmune network. These findings challenge the perception of nicotine pouches as low-risk products and highlight previously unrecognized neurological vulnerabilities associated with long-term use. The ability of inhaled CBD to reverse these pathological effects identifies a promising therapeutic strategy and underscores the need for further investigation into neuroimmune-glymphatic interactions in nicotine-related brain health.