Prostacyclin does not play any cytoprotective role in endothelial cell injury induced by 15-hydroperoxy-eicosatetraenoic acid, an arachidonate lipoxygenase product

Among various arachidonic acid metabolites examined, only 15(S)-hydroxperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE), a lipoxygenase product, caused a time- and dose-dependent injury to bovine endothelial cells in culture. There also occurred a significant inhibition of endothelial prostacyclin (PGI2) production due to 15-HPETE. But there were obvious dissociations in time course and dose dependence between 15-HPETE-induced cellular injury and 15-HPETE-induced inhibition of PGI2 synthesis. In addition, the cytotoxicity of 15-HPETE was not aggravated even when the endothelial monolayers were pretreated with several inhibitors of PGI2 synthesis. Also, some stable analogues of PGI2 had no protective effect on the injury. These results suggest that the reduced production of PGI2 caused by 15-HPETE is not directly associated with the onset of cellular injury, and that PGI2 does not play any cytoprotective role in endothelial cell injury induced by at least such lipid peroxides as 15-HPETE.