Dynamic responses of antioxidant enzymes in pearl oyster Pinctada martensii exposed to di(2-ethylhexyl) phthalate (DEHP)

Abstract

Di(2-ethylhexyl) phthalate (DEHP) is recognized as one of the most ubiquitous contaminants in marine environments and causes adverse effects on the health of marine organisms. The purpose of this study was to investigate the toxic effects of DEHP on the pearl oyster Pinctada martensii. The Pinctada martensii was exposed to 0.0, 0.5, 2, 8, or 32mgL−1 DEHP for 7 and 10days using parameters of antioxidant. Antioxidant indicators included levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), peroxidase (POD), and total antioxidant capacity (T-AOC) in the gills and hepatopancreas of Pinctada martensii for 7 and 10days. Besides, we used the lowest observed effect concentration (LOEC) of five enzyme activities in different tissues of Pinctada martensii for 7 and 10days to compare sensitivity. The results showed that the gills were more sensitive than the hepatopancreas of Pinctada martensii and that GSH activity in the gills and CAT activity in the hepatopancreas might be suitable biomarkers after 7days of DEHP exposure. After 10days of DEHP exposure, the GSH activity and CAT activity in the gills and SOD activity in the hepatopancreas could be regarded as biomarkers. Compared to the LOEC, GSH activity in the gills and CAT activity in the hepatopancreas after 7days of DEHP exposure were more sensitive than any other biomarkers. In addition, after 10days of DEHP exposure, GSH activity in the gills and hepatopancreas were much more sensitive than other activities. In conclusion, GSH activity demonstrated its potential to be used as a biomarker for the monitoring of DEHP pollution in the marine environment.