A biotest for hepatotoxins using primary rat hepatocytes

Freshly prepared rat hepatocytes proved highly suitable for screening of cyanobacterial hepatotoxins (microcystins). Inparticular, short-term exposure to pure microcystins caused severe damage to hepatocytes. The most toxic microcystin variant was microcystin-LR. In contrast, various cell lines were insensitive to pure microcystin. Algal blooms from a variety of freshwater lakes and rivers were studied and the results, using hepatocyte testing, suggest that two types of toxic cyanobacteria blooms occur. One group exhibited high toxicity to hepatocytes and less or no cytotoxicity to cell lines, and these effects are likely due to microcystins. Another group was toxic to hepatocytes and permanent cells after a longer exposure period, which suggests the presence of other harmful substances.