A exposição embrionária-larval de Drosophila melanogaster ao estresse oxidativo causado por 2,2'-azobis-2-amidinopropano e nanopartículas de pontos quânticos de seleneto de cádmio

Abstract

When it occurs a large production of free radicals concerning the antioxidant defenses, we call it oxidative stress, and the excess of these oxidizing substances has harmful effects, such as lipid peroxidation and protein oxidation, in addition to damage to the genetic material, which may contribute to the development of several pathological conditions, drastically reducing the quality of life of the population. Therefore, a better understanding of the process by which the production of free radicals occurs, how their damage, and ways to minimize such damage is so important. Several factors contribute to oxidative stress and excess free radical production, including diet, lifestyle, and environmental conditions. The use of Drosophila Melanogaster in toxicology and biochemical mechanism research has many advantages due to the ability to implement controlled doses, the ease of assessing multiple developmental milestones within a short life cycle, and the ability to study large numbers of individuals at the same time. Exposure can be assessed at the embryonic, larval, pupal, and adult stages of development. This work evaluated the effects of exposure to 2,2′-azobis-2-amidinopropane and also magic size quantum dots functionalized with cadmium and selenium on larval development (egg-larvae) of Drosophila Melanogaster, being divided into two parts. The first focused on evaluating the effects on antioxidant defenses and oxidative damage of larvae exposed to the 2,2′-azobis-2-amidinopropane molecule. The results show morphological changes, cell death, and toxicity. In addition, a dramatic increase in MDA and AOPP was found, and an increase in SOD and CAT activity in larvae exposed to AAPH, because this compound, soluble in water and at physiological temperature, generates free radicals in vitro, as its decomposition generates a mol of nitrogen and two moles of carbon radicals. The carbon radical can combine to produce stable products or react with molecular oxygen to generate peroxyl radicals - maintaining a constant rate of free radical production in the developmental environment that can induce oxidative damage. And the second step was to investigate the effects of embryonic exposure to quantum dots of cadmium and selenium in Drosophila Melanogaster larvae, to markers of oxidative stress, tissue damage, apoptosis and toxicity. That’s results show that the oral ingestion of QD 0.3 mg/mL can to damage the midgut, reduce the hatching rate, and increase oxidative stress. Quantum dots have very interesting optical properties and are being used more and more in numerous applications, so understanding their effects on living biological models is very important. Our results indicate a model that allows studying oxidative stress and damage in the development of the embryonic gastrointestinal system, in addition to being capable to be used as a tool for screening molecules with antioxidant and protective potential.