N-Acetylcysteine Attenuates Aβ-Mediated Oxidative Stress, Blood–Brain Barrier Leakage, and Renal Dysfunction in 5xFAD Mice

Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) pathology and is closely linked to oxidative stress, which contributes to blood-brain barrier leakage, renal dysfunction, and cognitive decline. We investigated the effects of N-acetyl cysteine (NAC), an FDA-approved antioxidant, on oxidative stress, brain Aβ levels, barrier leakage, renal function, and cognition in 5xFAD mice. Eight-week-old 5xFAD mice were fed a rodent diet supplemented with 600 mg/kg_Diet NAC for 4 weeks; wild-type (WT) mice and control 5xFAD mice were fed a regular rodent diet. We detected elevated brain and renal 4-hydroxynonenal(4-HNE) levels, reduced creatinine clearance, and increased plasma S100β levels in untreated 5xFAD mice compared to WT controls. Untreated 5xFAD mice also had higher capillary leakage, reduced P-gp activity, and impaired cognition compared to WT. NAC treatment of 5xFAD mice reduced brain Aβ40 levels, normalized 4-HNE levels to control levels, improved creatinine clearance, decreased capillary leakage, and lowered S100β plasma levels. NAC improved cognitive performance in 5xFAD mice, as shown by Y-maze. Our findings indicate that Aβ-induced oxidative stress contributes to barrier dysfunction, renal impairment, and cognitive deficits in 5xFAD mice. Notably, NAC treatment mitigates these effects, suggesting its potential as an adjunct therapy for AD and other Aβ-related pathologies by reducing oxidative stress.