Metallothioneins as biomarker of environmental stress in Pontoporia blainvillei (Franciscana Dolphin), Argentina.

POLIZZI, P.; CHIODI BOUDET, L.; DENUNCIO, P.; RODRÍGUEZ, D.; GERPE, M.

Long Beach

Simposio; International Symposium on Pollutant Responses in Marine Organisms (PRIMO 16); 2011

The Franciscana is an endemic cetaceous inhabiting estuarine and coastal waters from Brazil (18ºS) to Argentina (42ºS). Metallothioneins (MTs) are involucrated in the homeostasis of essential metals, and they are also detoxified those without a physiological function. Moreover, MTs could play a role as modulator of immunological system, and could be involved in oxidative stress responses. The aim of the present study was to analyze concentrations of metallothioneins in liver, kidney and muscle of two geographical groups (North –NG- and South Group –SG-) of dolphins from two areas with different environmental impact. The area of NG corresponds to estuary of La Plata River, the most important river of Argentine, due to its flow and it covers the main urban and industrial centers, with a high degree of pollution. The area of SG corresponds to marine coast, with a very low or null impact. Metallothionein determination was performed by UV-Vis spectroscopy (5,5`ditiobis-2-dinitrobenzenoic acid, DTNB). The presence of MTs was checked through Western blot. All analyzed tissues presented higher levels from SG dolphins than those of NG. Both geographical groups presented the highest levels in muscle. A decrease of MTs concentrations with age was evident for liver of NG dolphins; however, kidney of those from SG showed an increment. A couple mother-foetus (from SG group) was analyzed. Liver showed the maximum levels found for both geographical areas, and the muscular tissue of mother was the maximum levels found for all studied animals. The high levels found in liver are associated to the requirement of high contents of zinc during the perinatal development, showing the relevance of MTs during this period. The MT results in Pontoporia blainvillei, a top predator usually exposure to environmental contaminant and several stressors, are the first review to allow future evaluation in a species qualify as vulnerable by the International Union for Conservation of Nature (IUCN). Pontoporia blainvillei, a top predator usually exposure to environmental contaminant and several stressors, are the first review to allow future evaluation in a species qualify as vulnerable by the International Union for Conservation of Nature (IUCN).