The Use of Intraarticular Hyaluronic Acid on the Treatment of Experimental Osteoarthritis: A Radiological and Histopathological Study on a Rabbit Stifle Joint


Abstract: This study was carried out an 21 male, 7-month-old, white New Zealand rabbits. The anterior cruciate ligaments in the stifle joints were excised in both knees under general anesthesia. At the end of the first month, 3 cases were sacrificed and were exposed to macroscopical, radiological and histopathological examinations to determine the occurrence of experimental osteoarthritis. In 18 cases, hyaluronic acid was injected into right stifle joints intraarticularly on the second and third months at a dose of 2mg/kg. Left stifle joints were considered to be control groups. At the end of the postoperative second month 9 cases and in the third month the remaining 9 cases were sacrificed. Stifle joint radiographs of cases in the postoperative first, second and third months were taken. The histopathological examination was carried out on the samples collected from the inner and outer compartments of the joint which were stained by Hematoxylin-Eosin and Toluidin Blue techniques. It was observed that the animal could use their right joints comfortably and without pain when the lameness was permanent in the left joints, where atrophy was observed. When two-view radiography of the left stifle joints was observed at the end of the first month superficial fibrillation, reduction in the cartilage thickness and osteophyter products were observed. These symptoms were progressive in the second and third months where they were absent in the right stifle joints. Radiological findings were evaluated using the Mann-Whitney Non-Parametric Method and a remarkable difference was found between the groups (p< 0.01). When the histological cross sections from the left stifle joint were examined, at the end of the postoperative first month a significant collagen degeneration and thinning of cartilage surface, fragmentation and clefting in the matrix were determined. In the metacromatic staining, metachromasy loss was present in cartilage joints when a muramidase increase was observed in synovial tissue. These symptoms progressed at the end of the postoperative second and third months. At the end of the postoperative third month, the osteoarthritis symptoms were considered to be more remarkable and degenerative changes were observed. In the right stifle joint, normal thickness and normal cellular activity were seen on the cartilage surface, where minimal synovial cell proliferation was observed. As a result of the metachromatic staining, cartilage matrix was normal and no fibrillation, fragmentation or clefting occurred. For the statistical analyses after Yates Intergroup Correction Test, Mann-Whitney, Non-Parametrical and Wilcoxon's Rank Sum Test for Period Samples tests were used and a significant difference was found between the groups (p< 0.01). In conclusion, it was determined that the experimental excision of the anterior cruciate ligaments of rabbits caused osteoarthritis. The changes occurring in the stifle joint tissues were followed histopathologically and radiologically for 3 months. Intraarticular hyaluronic acid application avoided the inflamation and degradation in the cartilage and synovial tissues.

Keywords: Hyaluronic acid, osteoarthritis, experimental study, stifle joint, rabbit.

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