Effects of sublethal Cd, Zn, and mixture exposures on antioxidant defense and oxidative stress parameters in early life stages of the purple sea urchin Strongylocentrotus purpuratus.
Aquat Toxicol
; 217: 105338, 2019 Dec.
Article
em En
| MEDLINE
| ID: mdl-31711008
ABSTRACT
Oxidative stress parameters were evaluated during the first 72â¯h of embryonic development of purple sea urchin Strongylocentrotus purpuratus continuously exposed to control conditions, to cadmium alone (Cd, 30⯵g/L), to zinc alone (Zn, 9⯵g/L) or to a Cd (28⯵g/L) plus Zn (9⯵g/L) mixture. These sublethal concentrations represent â¼ 10% of the acute EC50. Bioaccumulation, antioxidant capacity against peroxyl radicals (ACAP), total glutathione (GSH) level, glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PDH) and superoxide dismutase (SOD) activity, and lipid peroxidation (LPO) were analyzed at 24â¯h (blastula), 48â¯h (gastrula), and 72â¯h (pluteus) stages of development. Zinc (an essential metal) was well-regulated, whereas Cd (non-essential) bioaccumulated and whole-body [Cd] increased from blastula to pluteus stage in sea urchin larvae. In controls, ACAP progressively declined from 24â¯h to 72â¯h, while LPO reciprocally increased, but other parameters did not change. Cd alone was more potent than Zn alone as a pro-oxidant, with the major effects being decreases in SOD activity and parallel increases in LPO throughout development; GST activity also increased at 24â¯h. Zn alone caused only biphasic disturbances of ACAP. In all cases, the simultaneous presence of the other metal prevented the effects, and there was no instance where the oxidative stress response in the presence of the Cd/Zn mixture was greater than in the presence of either Cd or Zn alone. Therefore the sublethal effects of joint exposures were always less than additive or even protective, in agreement with classical toxicity data. Furthermore, our results indicate that SOD and Zn can play important roles in protecting sea urchin embryos against Cd-induced lipid peroxidation.
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Texto completo:
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes Químicos da Água
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Zinco
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Cádmio
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Estresse Oxidativo
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Strongylocentrotus purpuratus
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Antioxidantes
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article