Effect of intra-articular injection of mesenchymal stem cells in cartilage repair in experimental animals

Osteoarthritis (OA) is characterized by degeneration of the articular cartilage and, ultimately, joint destruction. Human umbilical cord blood (hUCB) may prove to be a new source of mesenchymal stem cells (MSCs) for cellular therapeutics used for cartilage repair.Aim of the workThis study was carried out over a nine-month period of time, to study the effect of intra-articular injection of hUCB MSCs in cartilage repair by histopathological and ultra structural assessment.Materials and methodsWe conducted our study on 20 adult rats, which were subjected to the induction of cartilaginous defect in both knee joints. This was followed by injection of MSCs suspended in Hyaluronic acid solution in the right knee of each rat while the left knee served as a control. Histopathological and electron microscopic studies were performed.ResultsThe present study revealed: In the injected knees; In 73% of the cases, the tissue was typical of fibrohyaline cartilage and appeared more cellular than fibrous. In 27% of the cases the repaired tissue appeared more fibrous than hyaline. In the control knees; the newly formed tissue was an undifferentiated connective tissue and the cells were covered with a thin layer of fibrous tissue. The electron microscopic pictures of the injected knees showed mitotic chondrocyte activity. The pictures indicated a repaired fibrohyaline cartilage.ConclusionWe can conclude that the intra-articular injection of hUCB MSCs is an effective method for cartilage repair in rats. This makes it a very promising tool for the treatment of patients with OA.