CHANGES IN THE CELLULAR COMPOSITION OF SYNOVIAL FLUID IN EXPERIMENTAL OSTEOARTHRITIS OF THE KNEE JOINT IN RABBITS

Abstract

Pathology of the locomotion system in animals of various species is one of the key issues. Osteoarthritis is common among large breed dogs and accounts for up to 85% of the total number of examined animals with "chronic" lameness. German and Eastern European Shepherds are most susceptible to osteoarthritis, accounting for 25% and 15% of the total number of dogs examined, respectively. At the age of 4 to 8 years, 90 % of dogs with osteoarthritis were found. The prevalence of pathology in males was found to be 4 times higher than in females. The study presents the peculiarities of changes in the cellular composition of synovial fluid taken from the knee joint of rabbits with experimentally modelled osteoarthritis of the knee joint in laboratory conditions of the joint using intra-articular Yellow peel 2*5 ml (manufacturer Medicare, Germany). The studies showed that synovial fluid plays an important role in the metabolic process inside the joint and contains many nutrients, and changes in the indicators on the 7th day were significantly different from those of the control group of animals that were intra-articularly injected with an isotonic 0.9% NaCl solution. It was noted that on the 7th day there was a clouding of the synovial fluid, the appearance of a pinkish tint and a more liquid character of the fluid. We found an increase in the level of eosinophils, macrophages, neutrophils and other cells compared to the control group of animals. The number of synovial cells decreased by 1.2 times compared to the control group. In animals of the experimental group on the 14th day of the study, the level of lymphocytes and macrophages increased, and the level of neutrophils remained constant, while the level of eosinophils decreased. In the experimental group of animals, on the 21st day of the experimental study, the pink tint of the punctured synovial fluid disappears, the colour becomes straw, the fluid becomes more viscous and remains cloudy. The level of macrophages and neutrophils decreases, but remains above the level of the control group of animals. We also noted the appearance of Tuton cells in the cytological samples, indicating the development of degenerative changes in the cartilage tissue in the joint. It was noted that in the animals of the experimental group on the 28th day of the study, the colour of the synovial fluid disappeared, but it remained cloudy. The level of neutrophils, eosinophils, lymphocytes and macrophages remained almost unchanged.