Reactive oxygen species generation and protein oxidative damage in the liver of Rana nigromaculata exposed to cadmium
镉致黑斑蛙肝脏中ROS生成及其蛋白质氧化损伤作用

To explore the degree of protein oxidative damage and its molecular mechanism in the liver of Rana nigromaculata upon exposure to cadmium, healthy adult frogs were exposed to 0.005, 0.010,0.050 or 0.100 mg·L-1 cadmium for 30 days. The protein carbonyl content was assessed with 2,4-dinitrophenylhydrazine and the amount of DNA-protein crosslinking was assayed with KCl-SDS. The level of reactive oxidizing species (ROS) in the liver was also detected. The results showed that the ROS level in mitochondria increased with the cadmium dose and there were significant differences between each cadmium-treated group and the control. Liver protein carbony1 (PCO) content and DNA content crosslinked with protein increased significantly with cadmium concentration, displaying an obvious concentration-effect relationship, but only at 0.05 and 0.1 mg·L-1 was the increase markedly significant. The results suggest that cadmium can induce protein oxidative damage and DNA damage; the primary mechanism may be generation of free radicals, followed by protein oxidative damage and DNA damage.