Synergistic regeneration of cartilage and bone using synovial fluid-derived MSCs and exosomes: A novel therapeutic strategy for osteoarthritis.

Osteoarthritis (OA) is the most common and progressive joint disorder, characterized by the slow breakdown of cartilage and the underlying bone. The leading cause of OA is age-related wear and tear of joint cartilage, often worsened by factors such as obesity, joint injuries, genetic predisposition, repetitive stress, and joint misalignment. Current medical interventions are limited in their ability to regenerate damaged tissues. While synovial fluid-derived mesenchymal stem cells (SF-MSCs) and their exosomes show distinct therapeutic promise, their combined efficacy remains largely unexplored. This study investigates their synergistic potential in a preclinical osteoarthritis model, which has been optimized for rapid deployment and field applicability in combat scenarios. A full-thickness cartilage defect model was established in Wistar rats (n = 30), divided into four groups: PBS control, SF-MSCs alone, exosomes alone, and a combination therapy group. Treatments were administered intra-articularly. The combination therapy resulted in an 85.3 % reduction in cartilage defect size and a 57.8 % increase in bone density by week 8. Histological analysis confirmed enhanced cartilage regeneration and extracellular matrix formation. qPCR data showed significant upregulation of osteogenic markers. This dual-platform, cell-free approach offers a minimally invasive and scalable therapy for combat-related joint injuries and osteoarthritis. Its combination of differentiation, paracrine signaling, and immunomodulatory mechanisms delivers superior regenerative efficacy.