The effects of two different crystalloid cardioplegic solutions on cultured human endothelial cells

The effects on cultured human endothelial cells of incubation with two standard crystalloid cardioplegic solutions (St. Thomas' and Bretschneider's) for one or five hours at 10 degrees C or 20 degrees C were studied. The cells were prelabelled with 51Cr and cell injury was measured by release of 51Cr, cell detachment, and by electron microscopy. The injury was also studied after a rewarming period of 35 minutes in cell culture medium at 37 degrees C. Endothelial cells incubated with cell culture medium, but otherwise treated in a similar way, served as controls. Both cardioplegic solutions caused significantly greater release of 51Cr than cell culture medium when incubated at 10 degrees C or 20 degrees C. The Bretschneider's solution induced slightly more release of 51Cr than did the St. Thomas' solution. The cells did not become detached during incubation. Electron microscopy of the cells after 5 hours with the cardioplegic solutions at 10 degrees C revealed contraction of the cells, mild intracellular oedema, swelling of mitochondria, and blebs or craters on the luminal surface of the cells. After rewarming in culture medium for 35 min the cells were not contracted and showed only minimal signs of injury, indicating a rapid and nearly complete reversibility of the changes. The present observations indicate that cultured endothelial cells get some protection, albeit not optimal, from the two crystalloid cardioplegic solutions tested. The presence of procaine-CL increased the injurious effect of the solutions.