RESUMO
OBJECTIVE: This study aimed to evaluate whether ligature-induced periodontitis and rheumatoid arthritis (RA) potentiate the deleterious effects on functional capacity, periodontal and synovial tissues, leukocyte migration, and interleukin 17 (IL-17) levels, and to investigate the repercussions of single Freund's Complete Adjuvant (FCA) injection associated with periodontitis. MATERIALS AND METHODS: Fifty-one male Wistar rats were randomised into six groups: control (CG, n = 8), RA (RAG, n = 9), periodontitis (PG, n = 9), periodontitis and RA (PRAG, n = 9), periodontitis and intradermal injection (PIDG, n = 9), and periodontitis and intra-articular injection (PIAG, n = 7). The animals underwent ligature placement and one or two injections with FCA to induce RA. Motor disability, nociceptive threshold, joint edema, and muscle strength were assessed, and the animals were euthanized on day 30. Synovial fluid, hemimandibles, and knee joints were collected. RESULTS: PRAG showed no reduction of edema or improvement of muscle strength, whereas it showed most significant changes in leukocyte migration, morphological analyses of the synovial membrane (SM), and radiographic and histometric analyses of the jaw. The PIAG showed some alterations, though not permanent. CONCLUSION: Ligature-induced periodontitis and RA induced by two FCA injections accentuated the deleterious effects on functional capacity, leukocyte migration, synovial and periodontal tissues.