This study was conducted to investigate the changes in the levels of antioxidant enzyme and structure of coronary arteries in long-term homocysteine administired rats and to investigate the effects of vitamin E on these changes.

For this purpose, 30 male and 30 female Wistar albino rats were used. The rats were randomly divided into 3 groups. These groups were named as control, homocysteine and vit-E. Normal saline was intraperitoneally administered to the control group; dl-homocysteine (0.71 mg/kg) was intraperitoneally administered to the homocysteine group; dl-homocysteine (0.71 mg/kg) + dl-α tocopheryl acetate (125 mg/kg) were intraperitoneally administered to the vit-E group daily for 6 weeks.

Compared to the control group, levels of plasma homocysteine, MDA and tissue MDA significantly (P<0.05) increased in homocysteine group, while significantly (P<0.05) decreased in vit-E group. When compared to the control group, levels of plasma SOD, GSH, GSH-Px, CAT and tissue GSH, GSH-Px significantly (P<0.05) decreased in homocysteine group, whereas significantly (P<0.05) increased in vit-E group.

Degeneration, cell infiltration and thickness were determined in the endothelium of coronary artery of homocysteine group in comparison to the control group.

In conclusion, administration of homocysteine caused an increase in the levels of plasma homocysteine, MDA and tissue MDA, while it caused a decrease in the levels of plasma SOD, CAT, GSH, GSH-Px and tissue GSH, GSH-Px. On the other hand, administration of vitamin E decreased the levels of plasma homocysteine, MDA and tissue MDA, while it increased the levels of plasma SOD, CAT, GSH, GSH-Px and tissue GSH, GSH-Px.