Alterations observed in the endothelial HUVEC cell line exposed to pure Cylindrospermopsin

The cyanobacterial toxin Cylindrospermopsin (CYN) is receiving great interest due to its increasing presence in waterbodies, which has lead to recognize it as a potential threat to drinking water safety. CYN is a potent inhibitor of protein and glutathione synthesis. The present work studies for the first time the effects of CYN in endothelial cells. The basal cytotoxicity endpoints studied at 24 and 48 h were total protein content (PC), neutral red (NR) uptake and the tretazolium salt, MTS, reduction. Moreover, the effect of subcytotoxic concentrations of CYN on the generation of intracellular reactive oxygen species (ROS), the activity of γ-glutamylcysteine synthetase (GCS) and glutathione (GSH) content have been investigated. In addition, morphological alterations of HUVEC cells subsequent to CYN exposure were recorded.The cytotoxicity endpoints revealed a decrease in the cellular viability in a time and concentration-dependent way. The most sensitive cytotoxicity endpoint was NR uptake assay, with reductions in cell viability of 95% at 48 h of exposure to 40 μg mL⁻¹ CYN. Intracellular ROS production was increased only at the lowest concentration assayed, while GCS activity and GSH content underwent concentration-dependent enhancements. The most remarkable morphological alterations observed were: nucleolar segregation with altered nuclei, degenerated Golgi apparatus, increases in the presence of granules and apoptosis.