Apoptotic effect of cyanobacterial extract on rat hepatocytes and human lymphocytes

Toxic cyanobacterial blooms are an increasing problem in Poland. The produc tion of cyanobacterial toxins and their presence in drinking and recreation al waters represent a growing danger to human and animal health. This is co nnected with the increase of cyanobacterial biomass caused by excessive eut rophication of the water ecosystem. There is evidence that cyanobacterial h epatotoxins can act as a potent promoter of primary liver cancer. The apopt otic effect of microcystins in Polish cyanobacterial bloom samples on rat h epatocytes and human lymphocytes was observed using light and fluorescence microscopy, flow cytometry, and electrophoretic analysis. The incubation ti me needed to observe the first morphological apoptotic changes in hepatocyt es was approximately 30 min; however, the characteristic biochemical change s in DNA were not observed even after 120 min. In lymphocyte cultures the m orphological changes characteristic for apoptosis were observed after 24 h of incubation and a 48-h incubation was found to be optimal for analysis of internucleosomal DNA fragmentation, which is one of the main biochemical h allmarks of programmed cell death. These cells are an easily isolated and i nexpensive material for medical diagnostics. Therefore the apoptotic change s, together with the clastogenic effect seen in lymphocyte cultures, are pr oposed as a future analytical method for these toxins. (C) 2001 by John Wil ey & Sons, Inc.