Oxygen consumption as a highly sensitive and non destructive biomarker of environmental stressors

HERKOVITS J.; D´ERAMO J. L; SZTRUM A. A; CASTAÑAGA L; GROSSKOPF D

Lima

Congreso; IX Congress of the Society of Environmental Toxicology and Chemistry (SETAC LA); 2009

SETAC LA

. The high priority to evaluate the potential hazard of a large number of physical and chemical agents on living organisms urge the identification of rapid, versatile, non-destructive, highly sensitive and easy generation of dose and time dependent responses methods for screening purposes. Oxygen consumption is a paramount physiological and metabolic parameter in place from over 2.000 million years from prokaryotic to vertebrate organisms. It is well known that it is very sensitive to slight changes in living condition. Although there are contributions from more than 50years ago on the possibility to evaluate toxicity by means of oxygen consumption, its potential as a non-invasive, rapid and highly sensitive biomarker of environmental stressors was not evaluated. I will focus on oxygen consumption as a non-destructive biomarker with high potential for hazard assessment, anticipating severe adverse effects and for screening purposes   Amphibian embryos are very susceptible to environmental stressors. The higher susceptibility to noxious agents is frequently registered during the organogenic stages. Oxygen consumption change dramatically during ontogenesis from almost 0 in blastula, increasing from gastrula stage onwards from 1 to 50.4uL oxygen X 10-3/ embryo/min at complete operculum stage (S25). It is noteworthy that after the open mouth stage (S23) the increase in oxygen consumption is correlated with food availability.  These remarkable changes in oxygen consumption during embryonic development provide a unique opportunity to evaluate the adverse effects of noxious agents on oxygen consumption in different metabolic as well as physiological conditions including independent or food dependent stages. For standard studies we selected to conduct oxygen consumption in embryos at the last developmental stage because organ, tissue and cellular complexity is higher including neuro-muscular, digestive, urinary and respiratory systems are in place and the oxygen consumption itself is at a maximum level. The noxious agents evaluated were Cd, Al and Ni. As a general pattern the oxygen consumption diminish in a dose and time dependent  response to the metal in the maintaining media, the method sensitivity was over one order of magnitude below to lethal effects and a reduction over 50% in the oxygen consumption in the experimental embryos anticipate at least with 24hs lethal effects. Our results contribute to consider oxygen consumption as a rapid and robust non-destructive biomarker suited for large-scale monitoring programs.