“…Methods of euthanasia may impact the study results, either directly with qualitative or quantitative changes of a parameter to be measured, or even generating histological changes, or indirectly, due to the circumstances associated to the technique, handling and exposure to other animals killed 22 . Most studies adopts as a technique of euthanasia the injection of overdose of barbiturates, for instance, pentobarbital sodium 2,7,9,10,23 , or injection of potassium chloride 6,8 , up to a recognition of the animal's death, through the absence of heartbeats, breathing movements and reflexes.…”