A novel method for establishing a rat model of knee osteoarthritis: knee joint fixation using medical polyurethane composite wraps

Background: Knee osteoarthritis (KOA) is a leading cause of chronic pain and disability in humans, companion and farm animals, with socioeconomic burden and animal welfare concerns. KOA models are essential for advancing diagnostics, therapies, and preventive strategies. This study aimed to establish a reliable non-invasive rat KOA model and evaluate its translational value for comparative and clinical medicine. Methods: = 10). KOA was induced in the model group by immobilizing the knee joint through circular fixation using a medical polyurethane composite bandage. Following the modeling phase, knee cartilage was macroscopically evaluated. Functional impairment was assessed using the Modified Lequesne MG scale. Imaging analyses comprised 7.0 T magnetic resonance imaging (MRI) and micro-computed tomography (Micro-CT) to examine structural and morphological alterations in the knee joint. The histological assessment included Safranin O-Fast Green staining to assess cartilage degradation using the Osteoarthritis Research Society International (OARSI) scoring system. Chondrocyte apoptosis was identified through terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Results: < 0.01). The model induction success rate exceeded 95%, with a complication rate below 5%. Conclusion: We developed a non-invasive rat KOA model using polyurethane bandage immobilization that recapitulates cross-species progressive OA pathology. This robust, low-cost platform enables early biomarker screening, disease-modifying therapy evaluation, and preventive intervention validation for veterinary/human OA, highlighting its translational value for comparative and clinical medicine.