MORPHOGENESIS OF KNEE HYALINE CARTILAGE DURING INTRAARTICULAR INJECTION OF PLATELET-RICH AUTOLOGOUS PLASMA AND/OR HYALURONIC ACID PREPARATION IN RATS WITH EXPERIMENTAL OSTEOARTHRITIS

According to current concepts, the influence of autologous platelet-rich plasma (PRP) and high molecular hyaluronates (HA) on the repair of hyaline cartilage during its inflammatory and degenerative changes has been insufficiently studied yet. The objective of the work was to evaluate the morphological changes in the structure of hyaline cartilage in experimental osteoarthritis after intra-articular injection of PRP and/or HA. Material and methods. The authors used 50 adult rats of Wistar line, weighing 250±2,2 g., distributed into five groups of 10 animals (two control and three experimental groups). An experimental gonarthosis was simulated on four groups of animals. Animals of the first experimental group received intra-articular injection of PRP, the second group – HA, the third – both PRP and HA. Results. No morphological signs of degenerative and inflammatory changes in the first control group were identified. Following osteoarthritis simulation the articular cartilage thinned to 121±20,4 microns (p<0,05) and the volume fraction of chondrocyte decreased to 1,2±0,6% (p<0,05). The authors observed an uneven coloration of collagen fibers with severe tinctorial properties disorder of the articular cartilage matrix. After the RPR introduction the authors observed tickening of the articular cartilage up to 275±18,9 micron (p<0,05) and the volume fraction of chondrocytes up to 18,4±2,0% (p<0,05). The contour of the cartilage surface became smoother with the formation of a cell-free zone. Collagen fibers demonstrated a uniform distribution, tinctorial properties of cartilage matrix in all areas were preserved, no signs of inflammation were noted. After HA introduction the authors observed thickening of the cartilage plate up to 264±21,3 microns (p<0,05) and the volume fraction of chondrocytes up to 11,6±1,2% (p<0,05). The surface of the cartilage featured uneven contours due to multiple areas of pulping. Uneven tinctorial properties of cartilage matrix, thickness and orientation of collagen fibres were retained. No signes of inflammation were observed. After the combined consecutive application of PRP and HA cartilage thickness increased up to 268±15,3 microns (p<0,05) and the volume fraction of chondrocytes increased up to 12,7±0,9% (p<0,05). Individual portions of pulping on the cartilage surface were observed. Tinctorial properties of the cartilage matrix were preserved; the focal uneven staining of collagen fibers in the basal zone was observed. No signs of inflammation were noted. Conclusion. During osteoarthritis simulation in knee joints of experimental Wistar line rats the authors observed severe structural changes in articular hyaline cartilage including complete destruction accompanied by vascular proliferation and granulomatous inflammation. Intraarticular injections of PRP, HA as well as PRP in combination with HA during the simulation of osteoarthrosis were accompanied by a decrease in the severity of degenerative and dystrophic processes and improval of tinctorial properties of articular cartilage matrix. Sole application of PRP or consecutive application of PRP followed by HA were observed as having the more significant reparative effect on articular cartilage as compared to HA.

osteoarthritis, high molecular hyaluronate, autologous platelet-rich plasma, articular cartilage, inflammation