Paracrine Effect of Synovial-Derived Stem Cells on Induced Knee Osteoarthritis in Rats

Background: Osteoarthritis (OA) is a progressive degenerative disease. Previous treatment strategieshave tried to slow the progress of OA. Objectives: The present study aimed to stop and reverse the progressive nature of OA by the paracrine effects of synovial stem cells. Methods: Fifty male Sprague Dawley rats were randomly allocated to five equal groups (n = 10). The control group received no treatment. The second group received an intra-articular Hyalgan injection. The third group received an intra-articular injection of secreta. The fourth group received an intra-articular injection of synovial-derived stem cells (5 x 10^6). The last group received an intra-articular injection of secreta combined with synovial-derived stem cells (5x10^6). Three months after treatment, the samples were harvested and evaluated by histopathological and radiological analyses. Results: Histopathological and radiological findings demonstrated significant differences between the synovial stem cell combined with the secreta group and the control and Hyalgan groups. Significant differences were observed in the subchondral bone and matrix scores between the secreta group and the synovial stem cell and Hyalgan groups (P-value = 0.042 and P-value = 0.0001, respectively). Both secreta and synovial stem cell groups showed better healing in terms of cell population viability index than the Hyalgan group (P-value = 0.015 and P-value = 0.005, respectively). The synovial stem cell combined with secreta group showed a significant difference from the synovia stem cell group in both medial femoral condyle and fabella osteophyte indices (P-value = 0.004 and P-value = 0.011, respectively). Conclusions: The group treated with synovial stem cells combined with secreta showed better outcomes than other groups in histopathological and radiological evaluations.