The Effect of Mesenchymal Stem Cells and Aqueous Extract of Elaeagnus Angustifolia on the Mechanical Properties of Articular Cartilage in an Experimental Model of Rat Osteoarthritis

Introduction: Although, the effect of direct intra-articular injection of bone marrow stem cells (BMSCs) on the repair of articular cartilage and the effect of Elaeagnus angustifolia extract on pain relief in patients with osteoarthritis have been investigated, no studies has been conducted to compare the effects of these two therapeutic methods on the mechanical properties of articular cartilage. In the present stuy, the effect of these two methods on the mechanical strength of knee articular cartilage in a model of rat osteoarthritis has been studied. Methods: In the present research, 48 mature, male Wistar rats were used. Animals were randomly divided into 6 groups of 8 as follows: control group (healthy animals), saline with mono-iodoacetate (MIA), MIA with Elaeagnus angustifolia extract, MIA with BMSCs, and MIA with a combination of Elaeagnus angustifolia extract and BMSCs. Osteoarthritis was induced by injection of 50 &muL solution of MIA in rats of groups 3 to 6. About 500 mg/kg Elaeagnus angustifolia extract was injected intraperitoneally daily for 4 weeks and nonautologous mesenchymal stem cells were injected into the knee joint on the 14th day. Stress-relaxation test was conducted applying 0.1 mm displacement at the rate of 5 mm/min for 1000 seconds. Then, the maximum initial force, instantaneous stiffness,equilibrium force, and equilibrium stiffness were calculated. Results: Induction of osteoarthritis model decreased instantaneous stiffness, maximum initial force, and equilibrium stiffness as compared to the healthy group (P=0.05). Using Elaeagnus angustifolia extract and bone marrow stem cells increased instantaneous stiffness and equilibrium stiffness compared to MIA group, although this increase was statistically significant only in the BMSCs group (P=0.04 and P=0.026, respectively). In the BMSCs group, maximum initial force also significantly increased compared to MIA group (P=0.04). Conclusion: Apparently direct injection of BMSCs into the knee joint with osteoarthritis is more effective in increasing mechanical strength of the cartilage and improving the performance of the weight-bearing joint compared to using Elaeagnus angustifolia extract.