Caracterização do estado redox em modelo animal de hipóxia neonatal

Abstract

Perinatal asphyxia resulting in hypoxic-ischemic encephalopathy (HIE) affects millions of newborns worldwide, and more than half of survivors continue to develop cerebral palsy, epilepsy, and other forms of neurological impairment throughout their lives. These complications in neonates mainly result from the imbalance between the generation of oxidant substances and the interaction of the antioxidant defense system, a condition known as oxidative stress, where there is too much presence of oxidants in relation to antioxidants. More research is needed to develop already characterized results of post-hypoxic encephalopathy and to know the effects of oxidative stress on the response to this injury, in addition to establishing a similar model with the physiology of neonates, since the damage and repair mechanisms change with age. The newborn piglet reaches a degree of maturity at birth similar to that of humans in relation to cardiovascular regulation, being considered an excellent laboratory model for studies of human children, therefore, an animal model of disease with neonatal pigs was proposed for the characterzation of post-hypoxia oxidative stress, without the use of anesthesia. Ten healthy Large White newborn piglets of both sexes were randomly divided into two groups and submitted to an experimental hypoxia protocol by reducing the fraction of inspired oxygen. Hypoxia group, composed of 6 animals, was submitted to a reduction in fraction of inspired oxygen for 180 minutes. Control group animals (n=4) were manipulated and evaluated simultaneously. There was a significant difference in oximetry and heart rate in hypoxia group compared to control group (p<0.05). Swine brains were analyzed and the results found in this study presented an overview of brain oxidative stress developed in piglets as an animal model of neonatal hypoxia. Analysis of reduced glutathione (GSH) content, activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the content of lipid peroxidation (TBARS), carbonyl protein (PC) and myeloperoxidase (MPO) were performed. in order to contribute to other studies in the treatment of neonatal hypoxia. The present study contributes to the use of the piglet as an animal model of neonatal hypoxia and brain damage. There was a significant difference in heart rate and oximetry of the groups compared during hypoxia (p<0.05) and a greater trend in SOD and CAT activities in the hypoxia group, but no statistically significant difference (p>0.05). The values of the characterization of the redox state in the animal model of hypoxia present parameters from which new studies can be developed. Descriptors: antioxidants; swine; neonates