Envolvimento das poliaminas no ataque agudo de gota em camundongos

Abstract

Gout attack is characterized severe joint pain and inflammation with concomitant accumulation of monosodium urate (MSU) crystals. However, gout and the mechanisms responsible for the acute attacks are poorly understood, leading to improper treatment of the patient and reducing the quality of life. Polyamines (putrescine, spermidine and spermine) are involved in inflammatory nociceptive processes and have not been investigated to date. Therefore, the aim of the present study was to investigate the involvement of polyamines in the development of acute gout attack. Arthritis score, a compound measure of joint compromise that considers edema formation, erythema and paw position, mechanical hyperalgesia and inflammatory parameters were measured in an acute gout attack model in male mice induced by intra-articular (i.a.) injection of MSU, H2O2, phorbol 12-myristate 13-acetate (PMA), L-ornithine or polyamines (putrescine, spermidine, spermine). All these algogenic agents increased arthritis score in a dose-dependent manner with ED50 of 0.73 (0.4-1.1) mg/site for MSU, 2.3 (1.5-3.5) μmol/site for H2O2, 3.5 (2.1-5.6) nmol/site for PMA, 0.6 (0.3-1.1) μmol/site for L-ornithine, 0.8 (0.4-1.7) μmol/site for putrescine, 3.6 (2.6-5.1) μmol/site for spermidine and 0.1 (0.06-0.2) μmol/site for spermine. All tested algogenic agents caused joint edema and nociception, except putrescine, which increased only arthritis score. α-Difluoromethylornithine (DFMO; ornithine decarboxylase ODC - inhibitor, i.a.) prevented MSU-, H2O2-, PMA-, L-ornithine-induced nociception, but not edema. On the other hand, DFMO did not prevent spermine-induced edema and nociception. DFMO prevented MSU-induced increase of ODC activity. Our results indicate that polyamines contribute to acute gout attacks, suggesting that inhibitors of polyamine synthesis may be potential therapeutic agents for the treatment and prophylaxis of gout.