Short-term responses to cadmium exposure in the estuarine polychaete Laeonereis acuta (Polychaeta, Nereididae) subcellular distribution and oxidative stress generation

Abstract

Some effects of cadmium exposure (100 mg/L for 4, 8, 12, and 24h) on the estuarine polychaete Laeonereisacuta (Nereididae) were evaluated. This polychaete was able to accumulate cadmium in the body, with the metal stored mainly in the cytosolic fraction (.10kDa). Activity of the antioxidant enzymes superoxide dismutase, glutathione S-transferase, and glutathione reductase (GR) as well as the total oxyradical scavenger capacity, the glutamate cysteine ligase catalytic subunit gene expression, and the metallothionein-like proteins content were not affected by cadmium at any exposure time tested. Catalase(CAT)activity, however, was significantly lower (p , 0.05) in worms treated with cadmium compared with that in control safter 8h of exposure. At the same exposure time, lipid peroxide levels were increased(p , 0.05) in worms exposed to cadmium compared with those in control worms. Interestingly, CAT and GR activities decreased overtime(p , 0.05) independent of cadmium treatment, which is a result that could be attributed to starvation. The effects caused by cadmium in the present study were observed only after 8h of exposure, demonstrating that cadmium can generate oxidative stress.