TERATOGENESIS: THE STAGE-DEPENDENT SUSCEPTIBILITY OF AMPHIBIAN EMBRYOS TO ENVIRONMENTAL STRESS

JORGE HERKOVITS1, LUIS A. CASTAÑAGA1, MARÍA T. SANDOVAL2, CAROLINA M. ARONZON AND CRISTINA S. PÉREZ-COLL1,3

Jackson, Mississippi, EEUU

Simposio; Third International Symposium on Recent Advances in Environmetal Health Research; 2006

Jackson State University

Abstract: Living organisms at developmental stages are very susceptible to physico-chemical stressors. As teratogenic agents usually produce also mutagenic and carcinogenic effects, malformations are very relevant end points for adverse effects of single physico-chemical agents, complex mixtures and environmental samples. By focusing on the stage-dependent susceptibility to noxious agents, in this study, the most susceptible developmental stages will be reported for UV-B irradiation, H2O2,  lead, cadmium,  naringenin, and an organometalic fungicide (funguicygon) as examples of exposure to different physico-chemical agents. Although certain malformations such as delayed development, axial incurvations, reduced body size, microcephaly, hydropesy; epithelial ridges, wavy tails, etc. could result from the exposure to different physico-chemical agents, the percentage of affected embryos could be different in each case and signature-like features could be identified in certain cases. As a general pattern the amphibian embryo exhibit: i) a very high resistance (for both lethal and teratogenic effects) at early developmental stages (blastula-gastrula and even neurula); ii) a very high susceptibility at early organogenic stages (from neuromuscular activity to gill circulation stages) and iii) by the end of the embryonic development (from opercular folds onwards) a gradual increase in the resistance to noxious agents. Thus, the exposure to environmental stressors during the organogenesis stages seems to reflect the worst exposure condition scenarios, at least in amphibian embryos for both lethal and teratogenic endpoints.   Keywords: Amphibian embryo, stage-dependent susceptibility, teratogenesis, lethality,   Acknowledgements: This research was financially supported by FONCYT (PICT 03/14375), and CONICET (PIP 2316/2317)