Toxicity evaluation of freshwater cyanobacterium Microcystis aeruginosa PCC 7806: II. Nephrotoxicity in rats.

Nephrotoxic potential of laboratory cultures of freshwater cyanobacterium (blue-green alga) Microcystis aeruginosa PCC 7806 (Pasteur Institute) was assessed in male rats. The animals were injected intraperitoneally with 0.5, 1.0 and 2.0 LD50 doses of lyophilized cell extract. Elevated plasma urea and creatinine levels were accompanied by decrease in protein and albumin levels, followed by hematuria, proteinuria and bilirubinuria. Also decrease in kidney lactate dehydrogenase and glutamic oxaloacetic transaminase indicated possible nephrotoxic potential of the cyanobacteria. The extract also produced various hematological changes associated with stagnant type of hypoxia. High performance liquid chromatography of the culture identified the active principle (toxin) as Microcystin-LR.