Dual protective role of curcumin- encapsulated chitosan nanoparticles against gastric and neural injury in a rat model of gut-brain axis dysfunction: a histological and biochemical study.

Gastric ulcer (GU) and Alzheimer's disease (AD) are prevalent age-associated disorders frequently accompanied by systemic oxidative stress and inflammation. Emerging evidence suggests that gastrointestinal dysfunction and inflammatory signaling may aggravate neurodegenerative processes. Curcumin (Cur) exhibits well-established antioxidant, anti-inflammatory, neuroprotective, and gastroprotective properties; however, its therapeutic utility is limited by poor bioavailability. The present study aimed to formulate and characterize Curcumin- encapsulated chitosan nanoparticles (Cur-CSNPs) and evaluate their dual protective effects in a clinically relevant comorbid rat model combining scopolamine-induced AD-like pathology and ethanol-induced GU. Male Wistar rats were divided into six groups: control, Cur-CS-NPs alone, GU, AD, GU + AD, and GU + AD treated with Cur-CSNPs. Behavioral assessments, biochemical analyses, histopathological evaluation, and immunohistochemical investigations were performed on brain and gastric tissues. GU + AD rats exhibited cognitive deficits, neuronal degeneration, amyloid-β accumulation, astrocyte activation, gastric mucosal injury, increased oxidative stress, NF-κB activation, elevated inflammatory cytokines, and enhanced apoptotic signaling. Cur-CSNP treatment significantly improved cognitive performance, reduced oxidative stress and inflammation, suppressed NF-κB signaling, decreased amyloid-β deposition, inhibited apoptosis, and restored gastric mucosal integrity. In conclusion, Cur-CSNPs exert concurrent neuroprotective and gastroprotective effects in a comorbid AD and GU model through coordinated modulation of oxidative stress, inflammation, amyloidogenic activity, and apoptotic pathways. These findings demonstrate that Cur-CSNPs exert dual neuroprotective and gastroprotective effects by modulating oxidative stress, inflammation, amyloidogenic pathways, and apoptosis, highlighting nano-curcumin as a promising therapeutic strategy for gut-brain axis-related disorders. Further investigations are warranted to elucidate the detailed molecular mechanisms and to explore the clinical applicability of nano-formulated curcumin as a therapeutic strategy for disorders involving concurrent gastrointestinal and neurodegenerative pathology.