Effect of cadmium on the antioxidant enzyme activity and lipid peroxidation in Sanguinolaria acuta

To explore the effects of cadmium (Cd2+) on the antioxidant enzyme activity and the Maglonydiadehyde (MDA) content in gills and digestive diverticula, Sanguinolaria acuta were exposed to Cd2+(at the concentration of 0.005 mg/L, 0.05 mg/L and 0.5 mg/L) for 24h, 72h and 120h, respectively. The antioxidant enzymes activities were investigated including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX), as indicators of antioxidant properties. The MDA content was also measured. Results suggested that there were no significant changes of SOD, CAT, GSH-PX activities in the gills and digestive diverticula at the concentration of 0.005 mg/L during the experimental periods. However the SOD, CAT and GSH-PX activities were significantly related to the exposure time and dosage at the concentration of 0.05 mg/L and 0.5 mg/L. The SOD, CAT and GSH-PX activities increased with the longer exposure time in the gills and digestive diverticula, and reached to the highest at the 72h, however, they all decreased at the 120h at the 0.05 mg/L. The activites of SOD in digestive diverticula and CAT in the gills and digestive diverticula reached to the highest at the 24h, but they all decreased at the 72h and 120h at the 0.5 mg/L.The CAT and SOD activities of digestive diverticula were even lower than the controls, which may attributed to the higher sensitive to Cd2+ than that in the gills. The activity of GSH-PX did not increased at the 24h and 72h in the gills at the 0.05 mg/L, and it was even lower than that in the controls, which maybe attribute to the combination of Cd2+ with the active site of GSH-PX. The MDA contents increased constantly with the longer exposure time and higher dosage of Cd2+ in the gills and digestive diverticula, which was different from that of the three antioxidant enzyme. It suggested that the MDA content in the gills and digestive diverticula can reflect the degree of oxidation damage, but it cannot reflect the degree of Cd2+ pollution in the water environment.