Histological and Immunohistochemical Study of the Possible Curative Effect of Intra-articular Injection of N-Acetyl Phenylalanine Glucosamine on Surgically Induced Osteoarthritis in Knee Joint of Adult Male Albino Rat

Background: Osteoarthritis (OA) is the most common degenerative joint disease for which there is no permanent treatment. The most affected structures are articular cartilage and subchondral bone. Knees are the most affected by OA, thus leading to severe disability. N-Acetyl phenylalanine glucosamine (NAPA) is a derivative of glucosamine (GlcN), which is one of the components of glycosaminoglycans (GAGs) of cartilage extracellular matrix (ECM).Aim: This work aimed to study the possible curative effect of N-acetyl phenylalanine glucosamine on surgically induced osteoarthritis in the knee joint of the adult male albino rat.Materials and Methods: This study was performed on 30 adult male albino rats. They were divided into three groups: group I included ten animals that were subdivided into two subgroups, IA (control) & IB (underwent Sham operation), group II included ten animals underwent destabilization of medial meniscus (DMM) surgery without receiving any treatment, group III included ten animals underwent DMM surgery then received a single intraarticular injection of NAPA after 4 weeks from the surgery and sacrificed 4 weeks later. At the end of the experiment, knee joints were obtained and processed for histological and immunohistochemical studies.Results: Hematoxylin and Eosin-stained sections showed a moderate degree of OA in group II that was improved in group III. Mallory’s trichrome stained sections revealed decreased collagen content in group II that was also improved in group III. The same results were found as regards the GAGs content of the cartilage matrix that was clearly decreased in group II and restored in group III.Conclusion: From the present study, it could be concluded that the osteoarthritic changes induced by surgical DMM in adult male albino rats can be improved by subsequent intra-articular administration of NAPA.