Objective: The accumulation of vascular smooth muscle cells (VSMCs) within the arterial intima is a key process in the pathogenesis
of atherosclerosis This is also one of the mechanisms leading to restenosis of coronary arteries following PTCA We have investigated the effect of the naturally occuring, lipid soluble antioxidant,
vitamin E on the intimal response to balloon injury in the
cholesterol fed rats Methods: Twenty four rats were assigned to 3 dietary groups at random: Ⅰ 1% cholesterol; Ⅱ 1% cholesterol with 0 5% vitamin E, and Ⅲ control chow Water was allowed ad libitum Balloon catheter deendotheliosation of the left common carotid artery was peformed by 3 passages of an inflated 2 F Fogarty embolectomy catheter 8 weeks after starting the experimental diet 12 days after the procedure, rats were killed by an overdose anaesthetic, and then perfused with paraformaldehyde to in situ fix the arteries After embedding with paraffin wax Sections were cut and stained with HE and immunohistochemstry Results: 1% cholesterol diet caused a significant increase in serum cholesterol in all rats on this diet compared to controls by the time to surgical treatment ( p <0 05) Neo intimal thickness and intimal/medial ratio in control chow group did not differ significantly from the rats receiving 1% cholesteroldiet These parameters were significantly lower in 1% choelsterol with 0 5% vitamin E group as compared to control and 1% cholesterol groups, respectively ( p <0 05) PCNA positive cells in both 1% cholesterol with 0 5% vitamin E and control groups were fewer than that in 1% cholesterol group ( p <0 05) Lesions in affected groups were predominantly composed of VSMCs, a few monocytes/macrophages were observed, either Conclusion: These data suggested that the reactive oxygen species may be involved in the intimal response to balloon injury, and that antioxidants, such as vitamin E may offer some protection against restenosis Although the way by which it does so is unclear, one possible mechanism is that by a direct inhibitory effect on the accumulation of VSMCs with the developing neo intima