TY - JOUR JF - انستیتو-پاستور-ایران JO - IBJ VL - 17 IS - 1 PY - 2013 Y1 - 2013/1/01 TI - Antioxidant Effects of Vitamins C and E on the Low-Density Lipoprotein Oxidation Mediated by Myeloperoxidase TT - تاثیر آنتی اکسیدانی ویتامینهای C و E بر اکسیده شدن لیپوپروتئین با دانسیته کم با واسطه میلوپراکسیداز N2 - Background: Oxidative modification of low-density lipoprotein (LDL) appears to be an early step in the pathogenesis of atherosclerosis. Meanwhile, myeloperoxidase (MPO)-catalyzed reaction is one of the potent pathway for LDL oxidation in vivo. The aim of this study was to evaluate in vitro antioxidant effects of vitamins C and E on LDL oxidation mediated by MPO. Methods: MPO was isolated from fresh plasma by sequential centrifugation using density ultracentrifugation. It was incubated with LDL and the LDL oxidation level was determined spectrophotometrically by measuring conjugated diene absorbance at 234 nm. Furthermore, vitamin C (50-200 mM) and vitamin E (10-40 mM) were added and the LDL oxidation level was determined. Results: The purity index of MPO and its enzymatic activity were 0.69 and 1127 U/mg protein, respectively. It was demonstrated that vitamin C in vitro inhibited LDL oxidation mediated by MPO however, vitamin E was unable to act in the same way. The protection by vitamin C was concentration dependent and maximum protective effect of vitamin C was observed at 150 mM, where about 64% of the LDL oxidation was inhibited. Vitamin C increased lag time of LDL oxidation mediated by MPO up to 2.4 times. Conclusion: It can be concluded from our results that vitamin C is able to improve LDL resistance to oxidative modification in vitro. In addition, vitamin C might be effective in LDL oxidation mediated by MPO in vivo, resulting in reduction of atherosclerosis process rate. SP - 22 EP - 28 AU - Samsam Shariat, Seyed Ziyae Aldin AU - Mostafavi, Sayed Abolfazl AU - Khakpour, Farzad AD - KW - Antioxidant KW - Myeloperoxidase (MPO) KW - Low-density lipoprotein (LDL) KW - Vitamin E UR - http://ibj.pasteur.ac.ir/article-1-798-en.html DO - 10.6091/ibj.1092.2012 ER -