RESUMO
Bisphenols are a class of compounds that exhibit a broad spectrum of antimicrobial activity. One of the most widely used member of this group is triclosan (TRN). TRN is a synthetic, non-ionic, broad-spectrum antimicrobial agent, which is incorporated into several products, including hand soaps and detergents and those of skin care and oral hygiene. The effects of TRN on mitochondrial respiratory parameters and the inner mitochondrial membrane potential (DeltaPsi) are described. That of TRN (up to 60 nmol mg(-1) protein) on isolated liver mitochondria decreased oxygen consumption of state 3 respiration, as well as DeltaPsi, but increased oxygen consumption of state 4 respiration, characteristic of an uncoupler effect. Analysis of segments of the respiratory chain suggested that the TRN inhibition site is located between complexes II and III. Mitochondrial swelling, energized or driven by the K+ diffusion potential using valinomycin, was also inhibited by TRN, the former being completely inhibited at concentrations greater than 10 nmol TRN mg(-1) protein, suggesting that it is also able to interfere with fluidity of the inner mitochondrial membrane. These results suggest that, besides its antibacterial effect, TRN can also impair the mitochondrial function of animal cells.
Assuntos
Anti-Infecciosos Locais/farmacologia , Fígado/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , Triclosan/farmacologia , Animais , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Relação Dose-Resposta a Droga , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/fisiologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mitocôndrias Hepáticas/enzimologia , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/fisiologia , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Ratos , Ratos Wistar , Desacopladores/farmacologiaRESUMO
Chlorhexidine (CHX) is a bis-bis-guanide with anphipatic and antiseptic properties and is largely used in dentistry, mainly for management of periodontal problems and in oral pre-operatory procedures. The present study concerns the effect of CHX on lipid peroxidation, mitochondrial permeability transition (MPT), and the interaction of CHX with ferritin (HoSF). CHX (100 microM) increased iron release from HoSF by approximately 13-fold when compared to control values. CHX also increased iron-dependent lipid peroxidation. MPT induced by CHX was protected by ethylene glycol-bis(beta-aminoethyl-ether)-N,N,N',N'-tetraacetic acid (EGTA), dithiothreitol (DTT), and cyclosporin A (CsA), showing a Ca2+-dependent effect, in which oxidation of thiol groups is involved, as well as the involvement of the transmembrane proteinaceous pore. BHT, catalase or o-phenanthroline did not protect MPT induced by CHX. This suggests that a ROS-independent mechanism is involved in the induction of MPT.