Effects of probucol on endothelial damage by 5-fluorouracil

Cardiotoxicity is a serious side effect of cancer treatment with the commonly used drug 5-fluorouracil (5-FU). The pathophysiology of this is unclear. Experimental studies show a thrombogenic effect of 5-FU, secondary to a direct toxic effect on the endothelium, possibly mediated by radical generation. Probucol is a lipid-lowering drug with strong antioxidant properties. The aim of this study was to evaluate the possibility of using probucol treatment to protect against the toxicity of 5-FU on vascular endothelium of the central artery in the ears of rabbits. Five groups of rabbits were treated with 1) 5-FU, 2) saline, 3) probucol high-dose and saline, 4) probucol high-dose and 5-FU, 5) probucol low-dose and 5-FU. Damage to the arterial endothelium was evaluated by scanning electron microscopy. Damage to the endothelium in 5-FU+probucol-treated animals was minimal and comparable to that of the control group. Intima disruption or thrombus formation was seen with 5-FU only. The results of the study indicate that treatment with probucol prevents 5-FU-induced endothelial injury.