Protective Effects of N-Acetylcysteine Against Acrylamide-Induced Lung Toxicity via Regulation of GSK-3β/Nrf2/NF-κB Signaling: Molecular and Immunohistochemical Evidence

Background: Acrylamide (ACR), a toxic compound formed during high-temperature cooking of carbohydrate-rich foods, is known to induce multi-organ toxicity, including oxidative and inflammatory lung injury. N-Acetylcysteine (NAC), a precursor of glutathione (GSH), possesses potent antioxidant and anti-inflammatory properties that may counteract ACR-induced pulmonary damage. This study investigated the protective effects of NAC against ACR-mediated lung toxicity, with an emphasis on the GSK-3β/Nrf2/NF-κB signaling axis. Methods: Forty male Wistar rats were allocated into four groups: control, NAC (250 mg/kg/day), ACR (50 mg/kg/day), and NAC + ACR. After 11 days of treatment, lung tissues were examined histopathologically using H&E, PAS, and Masson’s trichrome stains. Oxidative stress biomarkers (MDA, SOD, GPx, CAT, GSH) were quantified biochemically. Immunohistochemistry and qRT PCR assessed expression of Nrf2, NF-κB, IL-1β, and Caspase 3, while ELISA measured TNF α, IL-6, Bax, Bcl 2, and GSK 3β. Results: ACR exposure resulted in severe lung injury characterized by alveolar wall edema, epithelial hyperplasia, leukocytic infiltration, goblet cell hyperplasia, and peribronchiolar collagen deposition. These pathological changes were accompanied by a marked increase in MDA, NF-κB, IL-1β, TNF α, IL-6, Bax, Caspase 3, and GSK 3β, together with significant reductions in antioxidant enzymes and Nrf2/HO 1/NQO1 expression. NAC co-administration significantly ameliorated ACR-induced lung damage, restoring normal histological architecture, reducing fibrosis, and normalizing goblet cell activity. NAC also reversed oxidative stress, enhanced Nrf2 and downstream antioxidant responses, suppressed NF-κB-mediated inflammation, and mitigated apoptosis. Notably, NAC downregulated ACR-induced GSK 3β activation, thereby contributing to balanced redox and inflammatory signaling. Conclusions: NAC confers significant protection against ACR-induced pulmonary toxicity through its antioxidant, anti-inflammatory, and anti-apoptotic activities. These effects are mediated, at least in part, by modulation of the GSK 3β/Nrf2/NF-κB pathway. NAC demonstrates promising therapeutic potential for preventing chemically induced lung injury.