The mechanism of doxorubicin (DOX)-induced cardiotoxicity remains controversial. Wistar rats ( n = 66) received DOX injections intraperitoneally and were randomly assigned to 2 experimental protocols: (1) rats were killed before (−24 h, n = 8) and 24 h after (+24 h, n = 8) a single dose of DOX (4 mg/kg body weight) to determine the DOX acute effect and (2) rats ( n = 58) received 4 injections of DOX (4 mg/kg body weight/week) and were killed before the first injection (M0) and 1 week after each injection (M1, M2, M3, and M4) to determine the chronological effects. Animals used at M0 ( n = 8) were also used at moment −24 h of acute study. Cardiac total antioxidant performance (TAP), DNA damage, and morphology analyses were carried out at each time point. Single dose of DOX was associated with increased cardiac disarrangement, necrosis, and DNA damage (strand breaks (SBs) and oxidized pyrimidines) and decreased TAP. The chronological study showed an effect of a cumulative dose on body weight ( R = −0.99, p = 0.011), necrosis ( R = 1.00, p = 0.004), TAP ( R = 0.95, p = 0.049), and DNA SBs ( R = −0.95, p = 0.049). DNA SBs damage was negatively associated with TAP ( R = −0.98, p = 0.018), and necrosis ( R = −0.97, p = 0.027). Our results suggest that oxidative damage is associated with acute cardiotoxicity induced by a single dose of DOX only. Increased resistance to the oxidative stress is plausible for the multiple dose of DOX. Thus, different mechanisms may be involved in acute toxicity versus chronic toxicity.

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Resumo A Síndrome de Proteus é uma rara associação de malformações que podem afetar vários tecidos e órgãos. É caracterizada por macrodactilia bilateral, hipertrofia craniana, anomalias ósseas, escoliose, hamartomas de tecidos moles, nevo verrucoso pigmentar, anormalidades viscerais e outras hipertrofias. Há pouco mais de 200 casos notificados em todo o mundo. O presente artigo relata a evolução clínica de um paciente pediátrico com essa síndrome. A criança apresentou desnutrição grave associada ao extremo gigantismo de membros inferiores. Além disso, apresentou repercussões psicossociais relacionadas à exclusão social. A doença tornou-se mais grave e progrediu como síndrome consumptiva. Finalmente, os pais concordaram com a amputação dos membros inferiores hipertróficos. Um ano após as amputações, a criança estava totalmente reabilitada, protetizada dos membros amputados, com melhora nutricional, além de apresentar notória recuperação psicológica e reinserção social, o que representou melhora significativa da qualidade de vida para o paciente.