Nodularin is a hepatotoxin from a cyanobacterium, Nodularia spumigena, that inhibits
protein phosphatases 1 and 2 and posseses
tumor-promoting activity. The aim of this paper was to examine whether
nodularin is able to induce oxidative stress in mouse liver tissue and whether
melatonin (protective compound against oxidative damage) could supress the activity of
nodularin. We studied the effect of
nodularin (1, 5, and 10 microg/kg
body weight) and
melatonin (5, 10, and 15 mg/kg
body weight) administration on the activity of
superoxide dismutase (SOD),
catalase (CAT) and
glutathione peroxidase (GSH-Px) in mouse liver. Intraperitoneal treatment of mice with
nodularin per 7 days decreased the activities of all estimated
enzymes in a dose-dependent manner. Intraperitoneal treatment of animals with
melatonin per 7 days increased the activities of SOD, CAT, and GSH-Px and this effect was concentration-dependent. Co-treatment (
nodularin 5 microg/kg
body weight +
melatonin 5, 10, and 15 mg/kg
body weight per 7 days) and post-treatment with
melatonin (
nodularin 5 microg/kg
body weight per 7 days +
melatonin 5, 10, and 15 mg/kg
body weight per next 7 days) increased the activities of SOD, CAT, and GSH-Px in comparison to the
nodularin group. No significant differences from the
nodularin group were noted in the group after pre-treatment with
melatonin. In conclusion, these findings suggest that oxidative damage may be involved in the toxicity of
nodularin. Moreover, co-treatment and post-treatment with 10 and 15 mg/kg
body weight of
melatonin may protect against
nodularin-induced oxidative stress. There was no protective effect of pre-treatment with
melatonin.