Aortic endothelial cells damaged by a nitric oxide donor and protected by flavonoids

Cultured porcine aortic endothelial cells (PAEC) were exposed to four conce ntrations (0.00 mM - 5.00 mM) of 3-Morpholino-sydnonimine-hydrochloride (SI N-1, a nitric oxide donor). SIN-1 demonstrated a dose dependent cytotoxicit y against PAEC as indicated by the thiobarbituric acid (TBA) assay. Morphol ogically and biochemically, the presence of selected flavonoids (morin, que rcetin, or catechin) was shown to protect the PAEC from SIN-1 toxicity. Pro tection levels determined from the TEA assay were significant (p<0.05) for all flavonoids, with morin at 72+/-8%. Quercetin and catechin had comparabl e protective activities of 54+/-6% and 43+/-3%, respectively. This study su pports the contention that SIN-1 is cytotoxic to PAEC and that antioxidants such as flavonoids may attenuate such toxicity. (C) 1999 Elsevier Science Inc.