Stage Dependent Teratogenic and Lethal Effects Exerted By Ultraviolet B Radiation on Rhinella (Bufo) arenarum Embryos.

CASTAÑAGA, LUIS A; ASOREY, C; SANDOVAL, MARÍA T.; PÉREZ-COLL, C. S; ARGIBAY, T; HERKOVITS JORGE

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Año: 2009 p. 427 - 433

0730-7268

Abstract—The adverse effects of ultraviolet B radiation from 547.2 to 30,096 J/m2 on morphogenesis, cell differentiation, andlethality of amphibian embryos at six developmental stages were evaluated from 24 up to 168 h postexposure. The ultraviolet Bradiation lethal dose 10, 50, and 90 values were obtained for all developmental stages evaluated. The lethal dose 50 values,considered as the dose causing lethality in the 50% of the organisms exposed, in J/m2 at 168 h postexposure, ranged from 2,307to 18,930; gill circulation and blastula were the most susceptible and resistant stages, respectively. Ultraviolet B radiation causedmalformations in all developmental stages but was significantly more teratogenic at the gill circulation and complete operculumstages. Moreover, at the gill circulation stage, even the lowest dose (547.2 J/m2) resulted in malformations to 100% of embryos.The most common malformations were persistent yolk plug, bifid spine, reduced body size, delayed development, asymmetry,microcephaly and anencephaly, tail and body flexures toward the irradiated side, agenesia or partial gill development, abnormalpigment distribution, and hypermotility. The stage-dependent susceptibility to ultraviolet B radiation during amphibian embryogenesiscould be explained in the framework of evoecotoxicology, considering ontogenic features as biomarkers of environmentalsignatures of living forms ancestors during the evolutionary process. The stage-dependent susceptibility to ultraviolet B radiationon Rhinella (Bufo) arenarum embryos for both lethal and teratogenic effects could contribute to a better understanding of the roleof the increased ultraviolet B radiation on worldwide amphibian populations decline.