Oxidative and osmotolerant effects in Salvator merianae durante a hibernacao

Hibernation is a natural condition of animals that lives in the temperate zone, although some tropical lizards also experience hibernation annually, such as the lizard native from South America, Salvator merianae, or "tegu" lizard. Even though physiological and metabolic characteristic associated with hibernation have been extensively studied, possible alterations in the red blood cells (RBC) integrity during this period remains unclear. Dehydration and fasting are natural consequences of hibernating for several months and it could be related to some cellular modifications. In this study, we investigated if the osmotic tolerance of RBCs of tegu lizard under hibernation is different from the cells obtained from animals while normal activity. Additionally, we indirectly investigated if the RBCs membrane of hibernating tegus could be associated with oxidation by quantifying oxidized biomolecules and the activity of antioxidant enzymes. Our findings suggest that RBCs are more fragile during the hibernation period, although we did not find evidence of an oxidative stress scenario associated with the accentuated fragility. Even though we did not exclude the possibility of oxidative damage during hibernation, we suggested that an increased RBCs volume as a consequence of hypoosmotic blood during hibernation could also affect RBCs integrity as noted. Keywords: tegu, osmotic fragility, erythrocytes, oxidative stress. A hibernacao e uma condicao natural dos animais que vivem na zona temperada, embora alguns lagartos tropicais tambem experenciem hibernacao anualmente, como e o caso do lagarto nativo da America do Sul, Salvator merianae ou "teiu". Embora as caracteristicas fisiologicas e metabolicas associadas a hibernacao tenham sido amplamente estudadas, possiveis alteracoes na integridade das hemacias durante esse periodo ainda permanecem obscuras. A desidratacao e o jejum sao consequencias naturais da hibernacao por varios meses e podem estar relacionadas a algumas modificacoes celulares. Neste estudo, investigamos se a tolerancia osmotica de hemacias do lagarto teiu sob hibernacao sao diferentes das celulas obtidas de animais em atividade normal. Alem disso, investigamos indiretamente por meio da quantificacao de biomoleculas oxidadas e da atividade de enzimas antioxidantes se a membrana das hemacias dos teius em hibernacao poderia estar associada a oxidacao. Nossos resultados sugerem que as hemacias possuem maior fragilidade durante o periodo de hibernacao, embo