Estudos comportamentais e farmacológicos com a diacereína no modelo de monoartrite induzida por adjuvante completo de freund (CFA) em ratos

Abstract

Osteoarthritis (OA) is the most prevalent form of rheumatic disease which affects joints like the knee, with pain as one of the most frequent symptoms among patients. Traditionally, drugs used for treatment of OA do not reduce joint damage, and have several side effects. A drug studied for this purpose is diacerein (DIA), which provides anti-osteoarthritic and condroprotective effects and inhibits the activity of IL- 1â and cell migration. Additionally, studies show that DIA promotes joint pain relief in individuals with OA. Nevertheless, its effects have not been well established; therefore, studies which investigate the use of this drug and its implications in models of OA are necessary. This study aims to examine the pharmacological effect of DIA in the control of OA using a model of OA induced by intra-articular injection (i.a.) of CFA (complete Freund's adjuvant) in the rat knee. CFA induced hypersensitivity and inflammation for about 20 days, as well as joint effusion and changes in synovial membrane and cartilage, observed on histology (histological evaluations). Moreover, DIA (30 mg/ kg, orally, daily), significantly inhibited mechanical (58 ± 10% / 87 ± 3%) and thermal (66 ± 12 % / 87 ± 8 %) allodynia induced by injection of CFA, inhibited nociception in 83 ± 5 to 41 ± 11%, verified by the percentage of vocalization, in addition to reducing the score for spontaneous pain and joint swelling in 60 ± 6 to 40 ± 9 %. Furthermore, DIA reduced the histological changes induced by CFA after 3, 15 and 23 days of treatment. In short, this study extends the data described in the literature and shows that DIA (in the dose of 30 mg/kg) reduces the joint damage (joint effusion, changes in cartilage and synovial membrane) and nociception (mechanical and thermal allodynia and spontaneous nociception) associated with OA induced by CFA in rats. Efeito da diacereína em modelo de monoartrite (osteoartrite) em ratos, induzida por injeção intra-articular de CFA (adjuvante completo de Freund) no joelho de ratos. Análise da diacereína sobre a alodínia mecânica, nocicepção, edema articular e sobre as alterações histológicas induzidas pelo CFA após 3, 15 e 23 dias da indução da monoartrite, com tratamento diário com diacereína (na dose de 30 mg/kg).