BackgroundThis work aimed to study the homing evidence and the reparative effect of mesenchymal stem cells (MSCs) in the healing process of induced osteoarthritis in experimental animal model (donkeys).MethodsTwenty-seven donkeys were equally divided into 3 groups based on the observation period after induction of arthritis (3, 6 and 9 weeks) to achieve different degrees of osteoarthritis. Each group was subdivided into three subgroups of three animals each based on the follow-up period (1, 2 and 6 months) after treatment. The induction was done through intra-articular (IA) injection of 2 ml of Amphotericin-B in both carpal joints. MSCs were harvested in a separate procedure, labeled with green fluorescent protein (GFP) using monster GFP vector and suspended in hyaluronic acid for IA injection. Treatment approaches consisted of cell-treatment using MSCs suspended in 3 ml of hyaluronic acid (HA) for the right carpal joint; and using the same amount of (HA) but without MSCs for the left contralateral carpal joint to serve as a control. Animals were assessed clinically and radiologically before and after treatment. Synovial fluid was also evaluated. Histopathologically; articular cartilage structural changes, reduction of articular cartilage matrix staining, osteophyte formation, and subchondral bone plate thickening were graded. Data was summarized using median and percentile for scores of histopathologic grading. Comparison between groups was done using non-parametric Mann Whitney test.ResultsThe reparative effect of MSCs was significant both clinically and radiologically in all treated groups (P < 0.05) compared to the control groups. Fluorescence microscopy of sections of the cell-treated joints of all animals indicated that the GFP-transduced injected cells have participated effectively in the reparative process of the damaged articular surface and have integrated within the existing articular cartilage. The cells were associated with the surface of the cartilage and, were also detected in the interior.ConclusionsHoming was confirmed by the incorporation of injected GFP-labeled MSCs within the repaired newly formed cartilage. Significant recovery proves that the use of IA injection of autologous MSCs is a viable and a practical option for treating different degrees of osteoarthritis.

Regenerative therapies offer attractive alternatives for the treatment of chondral defects. Adipose-Derived Mesenchymal Stem Cells (AD-MSCs) found in the Stromal Vascular Fraction (SVF) allow the development of one-step surgical procedure by their abundant availability and a minimal invasive technique. Low Level Laser Irradiation (LLLI) of stem cells showed improved results on stem cell growth and proliferation. The aim of this study was to evaluate the treatment of chondral defects using single injection of laser activated SVF in a Platelet Rich Plasma (PRP) vehicle. Chondral defects were created surgically in the femoral condyle of 9 dogs, autologous adipose tissue was harvested from the abdomen and SVF was isolated, added to the PRP, laser irradiated and injected intraarticularly in the right joint. The left joint was injected normal saline as control negative. Evaluation of the treatment was done by physical examination, radiology and histopathology. Treated joints showed marked degree of cartilage regeneration and restoration of chondral histomorphological picture on the contrary of the control joints that showed deterioration over time and defect filling with only fibrous tissue forming a fibrocartilage at the end of 6 months period. The obtained results proved that the use of low level laser activated adipose derived stem cells is a safe, feasible technique as a single step surgical procedure and a very promising option for treatment of chondral defects.