The development of organ preservation solutions has been primarily accomplished in whole organ animal models. This study examines the toxicity of commonly used organ preservation solutions on endothelial cells in vitro. Primary human umbilical-vein endothelial cell cultures were incubated at 4 degrees C in solutions of 0.9% saline (NS), EuroCollins, ViaSpan (Belzer UW) (VIA), or Hank's balanced salts with 5% polyethylene glycol (PEG). Endothelial cell viability was ascertained by colormetric measurement of mitochondrial reduction of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to purple 1-(4,5-Dimethylthiazol-2-yl)-3,5-diphenylformazan. After exposure to hypothermic storage, cells were incubated at 37 degrees C in media with MTT, and the amount of reduced formazan present was quantified using a micro-ELISA spectrophotometer. Higher absorbance values were indicative of better cellular preservation. Cells stored in PEG displayed the highest viability at all time periods. ViaSpan provided better cellular protection than EC at longer storage intervals. This model allows for rapid assessment of preservation-induced endothelial cell injury and may aid development of improved storage techniques.