LIVER SLICE CULTURE FOR ASSESSING HEPATOTOXICITY OF FRESH-WATER CYANOBACTERIA

1 A modified mouse liver slice culture technique was established and t he viability of the system was assessed on the basis of leakage of cyt osolic enzymes viz. lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartic aminotransferase (AST) and slice histology. 2 This system was employed for toxicity screenin g of five algal species of Indian origin on the basis of the EC(50) fo r LDH leakage (dose of cyanobacteria resulting in leakage of 50% of en zyme) of a known toxic cyanobacterial strain Microcystis aeruginosa (P CC 7820). On the basis of both in vitro and in vivo toxicity none of t he five species screened exhibited toxicity. 3 The toxicity of PCC 782 0 was compared with a purified cyanobacterial hepatotoxin, Microcystin -LR. Various biochemical indices and histological changes confirm the hepatotoxic nature of the toxins. 4 The toxins did not induce glutathi one-mediated lipid peroxidation but they did cause significant mitocho ndrial damage based on an MTT assay. 5 The study illustrates the utili ty of this in vitro system in identifying naturally occurring toxic cy anobacteria, particularly hepatotoxic species.