Intra-Articular N-Acetylcysteine Reduces Synovitis Without Preventing Cartilage Degeneration in Experimental Osteoarthritis


Dinç M., Bayrak H. Ç., Karasu R., Aykaç B., Soydemir Ö. C., Saricetin A.

Biomedicines, cilt.14, sa.1, 2026 (SCI-Expanded, Scopus) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 14 Sayı: 1
  • Basım Tarihi: 2026
  • Doi Numarası: 10.3390/biomedicines14010086
  • Dergi Adı: Biomedicines
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Directory of Open Access Journals
  • Anahtar Kelimeler: cartilage degradation, intra-articular therapy, N-acetylcysteine, osteoarthritis, synovitis
  • Bursa Uludağ Üniversitesi Adresli: Evet

Özet

Background/Objectives: Osteoarthritis (OA) is a multifactorial degenerative joint disease characterized by synovial inflammation, oxidative stress, and progressive cartilage degeneration. This study investigated whether intra-articular N-acetylcysteine (NAC) attenuates synovial inflammation and oxidative stress and whether these effects translate into structural cartilage protection. Methods: OA was induced in rats by anterior cruciate ligament transection (ACLT). NAC (5 mg/50 µL) was administered intra-articularly once weekly for three weeks post-ACLT. Inflammatory cytokines (IL-1β, IL-6, TNF-α), oxidative stress markers (iNOS, TAS, TOS, OSI), and cartilage degradation markers (MMP-13, COMP, CTX-II) were quantified in synovial fluid and cartilage homogenates using ELISA. Cartilage integrity was evaluated histologically using the modified Mankin scoring system. Results: Compared with controls, NAC significantly reduced synovial IL-1β, IL-6, TNF-α, MMP-13, and iNOS levels and improved the synovial redox profile by increasing TAS and reducing TOS and OSI (all p < 0.05). In contrast, NAC did not significantly alter cartilage homogenate levels of inflammatory cytokines, oxidative stress indices, or degradation markers (COMP, CTX-II, MMP-13). Histological analysis demonstrated persistent cartilage fissuring, hypocellularity, and proteoglycan loss in both groups (p > 0.05). Conclusions: Intra-articular NAC exerts potent anti-inflammatory and antioxidative effects within the synovial compartment but fails to prevent cartilage degeneration in the ACLT model. These findings indicate a compartment-specific therapeutic profile, suggesting that NAC may function as a symptom-modifying agent in synovitis-dominant OA rather than a structure-modifying therapy. Future studies should focus on optimized delivery systems or combination strategies targeting cartilage and subchondral bone to achieve disease modification.