Abstract
Background: Knee osteoarthritis (OA) is a common and debilitating disorder marked by joint degradation, inflammation, and persistent pain. This study examined the possible therapeutic effects of curcumin and vitamin D on OA progression and pain in a rat knee OA model by anterior cruciate ligament transection and meniscectomy (ACLT + MMx). Methods: Male Wistar rats were categorized into five groups: control, curcumin-treated (100 mg/kg/day), vitamin D-treated (25 µg/kg/day), a combination of vitamin D and curcumin, and sham-operated. All supplements were administered orally on a daily basis for 12 weeks. Pain behaviors were assessed, serum biomarkers were measured, and knee histology was examined. Results: Both curcumin and vitamin D independently reduced pain, while the combined group exhibited better analgesic effects. Serum inflammatory cytokines demonstrated a decrease in pro-inflammatory cytokines and an elevation in anti-inflammatory cytokine interleukin-10 (IL-10) in the supplement groups. The antioxidative markers were partially recovered by curcumin and vitamin D supplement. However, the oxidative stress marker Cartilage Oligomeric Matrix Protein (COMP) was significantly reduced. Histology analysis revealed a preservation of joint architecture and cartilage integrity and decreased synovium inflammation in the groups treated with curcumin and vitamin D. Conclusions: Our findings indicate a dual mechanism that encompasses the role of anti-inflammation and antioxidation on knee OA progression and pain reduction, underscoring the potential of these natural chemicals as therapeutic agents for knee OA; curcumin and vitamin D supplement may be added in delaying knee OA progression and associated pain management in clinical patient care.