Abstract:

Objective: To explore the possible toxicological mechanisms of microcystin-LR (MC-LR) in mice. Methods: Organ index and blood biochemical parameters were examined in mice intraperioneally administered with microcystin-LR at the dose of 30 μg/kg bw at 1, 4 and 8 h postadministration. Results: A significant increase in liver index of mice treated with MC-LR at 4 h postadministration was observed; but no obvious change in kidney index was observed at this time point. A significant increase in blood catalase (CAT) content and activity was determined. An initial increase and final decrease in blood urea nitrogen (BUN) was also monitored; however, superoxide dismutase (SOD) only exhibited little change. Conclusions: MC-LR attracts hepatocytes first, produces a large amount of free radicals, destroys cell membranes and heptocytes, interrupts metabolism of amino acids, and results in hyperemia and swelling of liver. Followed by liver damage, kidney insufficiency is also initiated; permeability of kidney tubules is increased as a result of MC-LR treatment. As the time goes on, MC-LR causes a permanent damage to organism. This damage, however, is not seen apparently due to repair function in the organism, that is, the MC-LRcaused damage to organism is reversible to a certain extent.

Key words: microcystin-LR, action mechanism, organ index, biochemical parameters