Tracking and Therapeutic Effects of a Single Dose Wharton’s Jelly-derived Mesenchymal Stem Cell Intra-Articular Injection in a Guinea Pig Osteoarthritis Model Over 56 Days of Follow-up: A Pilot Study

Osteoarthritis (OA) is a major global health burden, affecting over 600 million people worldwide as of 2021, with numbers projected to rise significantly in the coming decades. Mesenchymal stem cell therapy is currently being investigated as a treatment option for knee OA. This study aimed to evaluate the persistence and therapeutic effects of human Wharton’s Jelly-derived mesenchymal stem cells (WJ-MSCs) following a single intra-articular injection (1.7 × 107 WJ-MSC cells/kg) in a guinea pig OA model, using six animals in the WJ-MSC treatment group and four animals in the control group. The primary endpoints are cartilage thickness, Osteoarthritis Research Society International (OARSI) cartilage degeneration scores measurements and persistence of WJ-MSCs. In this experiment, PKH26-labeled WJ-MSCs were injected into the right knee and tracked on days 0, 7, 14, 28 and 56. Knees were harvested on day 56 for macroscopic assessments, OARSI cartilage scoring, and histology using haematoxylin and eosin, and Safranin O staining. As a result, the WJ-MSCs remained persistent for up to 56 days. WJ-MSC-treated joints showed reduced OA severity, with increased cartilage thickness of 108% at the medial femur condyle (p = 0.002*), 36% at the lateral femoral condyle, 47% at the medial tibia plateau (p = 0.02*) and 45% at the lateral tibia plateau compared with controls. No signs of malignancy were observed. Overall, a single dose injection of WJ-MSC provided a proof-of-concept to conduct further research in the future.