A Histological Study on The Effect of Bone Marrow Derived Mesenchymal Stem Cells Suspended in Hyaluronic Acid on Articular Cartilage of Osteoarthritic Knee joint of Adult Male Albino Rat

Introduction: Current treatment strategies of osteoarthritis (OA) are restricted to short-term symptomatic relief by medical therapy. There is increasing evidence that bone marrow derived mesenchymal stem cells (BM-MSCs) represent a novel treatment for cartilage regeneration.Aim of the Work is to evaluate the therapeutic effect of intra-articular injection of BM-MSCs on the experimentally induced OA in the knee joint of adult male albino rat. Materials and Methods: fifty five adult male albino rats were used and divided into five groups. Group I served as a control group. Group II for harvesting BM-MSCs from the tibia and femur. Group III for induction of OA by intra-articular injection of monosodium iodoacetate (MIA) to be sacrificed after 2 weeks from induction. Group IV: Hyaluronic acid (HA) was injected in both normal knees to be examined after 4 and 8 weeks of injection of HA. Group V: Knee joint OA was induced as in group III. After 2 weeks, rats were injected with BM-MSCs suspended in HA (MSCs HA) in their knees. Knee joint specimens were examined after 4 and 8 weeks of MSCs-HA injection. Knee joint specimens were processed for histological study and stained with Hematoxylin and eosin, Mallory trichrome and fast green Safranin O stains. For immunohistochemical study, the number of CD44 positive chondrocytes was evaluated and the obtained morphological data were statistically analyzed. Results: OA knees treated with MSCs-HA showed well evidenced repair of the articular cartilage by hyaline-like cartilage in association with significant increase in the number of CD44 positive chondrocytes. Conclusion: Intra-articular injection of in vitro expanded BM-MSCs suspended in HA promotes articular cartilage repair by hyaline-like cartilage in MIA induced OA.