PARENT SESSION
PHA02 - Contaminant Effects on Amphibians & Reptiles
8:00 AM to 6:30 PM - Thursday, November 15, 2001
Exhibit Hall A
(PH059C) Stage-dependent Susceptibility of Naringenin in Bufo arenarum Embryos.
Pérez-Coll, C.S.1, Herkovits, J.1, Domínguez, O.1, 1
ABSTRACT- Naringenin is a flavonoid related to a wide spectrum of effects including anti oxidative stress, but the production of prooxidant metabolites was also reported. Among other adverse effects endocrine disruption and carcinogenesis were also informed. The aim of this study was to evaluate the effect of naringenin on the survival and morphogenesis of amphibian embryos by means of AMPHITOX as an Early-Life-Stage (ELS) and Chronic Toxicity (CT) test. The range of naringenin concentrations were from 5 to 30 mg/L. For ELS and CT 10 Bufo arenarum embryos, by triplicate, at 2-4 blastomeres stage (without jelly coats) and stage 25 (complete operculum) were maintained in the same concentration of naringenin. 30 mg/L naringenin exerted 100% lethality at gastrulae stages; 15 mg/L exerted lethality in 100% of the embryos by the end of gastrulae-initial neurulae stages; 10 mg/L exerted lethality in 70% of the embryos at neurula stage while 5 mg/L exerted lethality in 35% of the embryos at the same developmental stage. In all cases more expanded exposure periods increased the number of dead embryos. Regarding teratogenic effects, the main malformations were: reduced body size, axial incurvations, microcephaly, abdominal edema, underdeveloped gills and delayed development. Malformations were proportional with the concentration of naringenin in the maintaining media e.g. 5 mg/L exerted 55% of malformed individuals (35% of them died after 5 days of exposure, control stage: gill circulation). Scanning electronic microscopy showed alterations in epithelial cell shapes related to malformations. In the case of embryos at stage 25, 30 mg/L exerted 90% lethality within 48 hours of exposure, 15 mg/L exerted 33% lethality and 10 mg/L resulted the NOEC for naringenin. The results point out the high susceptibility of Bufo arenarum embryos to naringenin including its teratogenic effect during early life stages while the stage dependent susceptibility is related to the concentration of naringenin exerting adverse effects, both lethality and teratogenesis, at different developmental stages.
Key words: Naringenin, Early Life Stage, Malformations, Amphibian embryos