Morphological changes in the tissues of the rabbit knee joint due to experimental osteoarthritis after the use of mesenchymal stem cells

The purpose of the study was to investigate the regenerative processes in the knee joint of rabbits with experimental osteoarthritis after using of allogeneic bone marrow stem cells and a traditional treatment with the non-steroidal anti-inflammatory drug Meloxicam. For the experiment were used 27 male California rabbits (males). Three groups of animals were formed: a control group; the first experimental group treated by the traditional method; the second experimental group treated with allogeneic mesenchymal stem cells (MSC). Animals in the three groups were subjected to osteoarthritis of the knee joint by double injection of 3.44% retinol acetate into the joint cavity at a dose of 1 ml at intervals of 7 days. Tissue from the affected site was sampled for histological examination at 7, 14 and 28 days. The histological sections were stained with haematoxylin-eosin and examined under a microscope. It has been established that intra-articular administration of 3.5 × 106 cells of allogeneic MSCs in experimental osteoarthritis contributes to the restoration of the superficial layer of cartilage, as evidenced by the formation of columns of chondrocytes in the middle layer of articular cartilage and the appearance of isogenic groups of cartilage cells with basophilic cytoplasm in the matrix, uniform articular surface. The use of the traditional method of treating rabbits using the drug Meloxicam is accompanied by incomplete chondrogenesis: part of the chondrocytes is localized in typical chambers, in some cases chondrocyte chambers did not differentiate; articular cartilage had unequal thickness, cell placement was uneven.