Syringic acid attenuates LPS-induced acute lung injury via modulation of the HMGB1/TLR4/NF-κB and Keap1/Nrf2/HO-1 pathways: Mechanistic insights from in vivo and in silico studies


Laçin B. B., Şengül E., Yıldırım S., Aykurt F., Warda M. A. A., Çınar B., ...Daha Fazla

IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES, cilt.29, sa.2, 2026 (SCI-Expanded, Scopus) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 29 Sayı: 2
  • Basım Tarihi: 2026
  • Doi Numarası: 10.22038/ijbms.2026.90093.19427
  • Dergi Adı: IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, EMBASE, Index Islamicus, Directory of Open Access Journals
  • Atatürk Üniversitesi Adresli: Evet

Özet

Objective(s): Sepsis-induced acute lung injury (ALI), driven by uncontrolled inflammation and oxidative stress, remains a major cause of mortality in critically ill patients. This study aimed to investigate the protective and mechanistic effects of syringic acid (SA), a natural phenolic compound, against lipopolysaccharide (LPS)-induced ALI in rats. Materials and Methods: Male Sprague-Dawley rats were allocated into five groups: control, SA80, LPS, SA40+LPS, and SA80+LPS. SA was orally administered (40 or 80 mg/kg/day) for 14 days before a single intraperitoneal injection of LPS (10 mg/kg). Lung tissues were collected 12 hr post-LPS for histopathological, biochemical, and molecular evaluations. In silico docking using Schr & ouml;dinger Maestro (2025/1) assessed SA interaction with the KEAP1 Kelch domain (PDB: 5FZN). Results: LPS challenge caused severe pulmonary edema, inflammatory infiltration, elevated proinflammatory cytokines, lipid peroxidation, and reduced antioxidant enzyme activities. SA pretreatment, particularly at 80 mg/kg, significantly (P<0.05) alleviated these alterations. Mechanistically, SA down-regulated the HMGB1/TLR4/NF-kappa B signaling cascade and activated the Keap1/Nrf2/HO-1 antioxidant pathway. Reduced 8-OHdG and caspase-3 expression indicated mitigation of oxidative DNA damage and apoptosis. Docking analysis revealed strong binding affinity and favorable MM-GBSA scores for SA within the KEAP1 active pocket, suggesting direct modulation of Nrf2 activation. Conclusion: SA confers potent protection against LPS-induced ALI through coordinated antiinflammatory and antioxidant mechanisms involving HMGB1/TLR4/NF-kappa B inhibition and Keap1/ Nrf2/HO-1 activation. These findings highlight SA as a promising therapeutic candidate for sepsisassociated pulmonary injury.