Study About The Antioxidant Function Of Radish Phospholipid Hydroperoxide Glutathione Peroxidase

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) was considered to be effective against phospholipid membrane peroxidation. Since 1982, when PHGPx was purified from liver of pig as an antioxidant enzyme, its enzymatic functions and properties have been extensively studied. It has been well reported that overexpression of PHGPx genes play an important role in protecting host cells from oxidative injury in several model systems. However, the effects of exogenous PHGPx protein have not been well reported yet. In this study, radish phospholipid hydroperoxide glutathione peroxidase (RsPHGPx), which possesses the highest catalystical activity in plant PHGPx family, was purified and applied into NIH3T3 fibroblasts, in order to examine its ability in protecting cells against hydroperoxide-mediated injury.Cell morphological, cell viability and MDA assay shows that RsPHGPx can protect cells against hydroperoxide-mediated injury. Cells preincubated with active RsPHGPx exhibited higher cell viability and lower MDA levels after hydroperoxide exposure, suggesting that the protective potency of RsPHGPx resulted from its enzymatic activity and exogenous RsPHGPx could protect mouse 3T3 fibroblasts against the injurious effects of hydroperoxides. Furthermore, morphological research suggests that the cells preincubated by RsPHGPx maintain its normal shape, while comparing with the cells treated with only H2O2. The mophologiacal results validate the cell viability and MDA assay.In addition, the level of intracellular reactive oxygen species was measured via DCFH-DA method, which shows coherent results with the MTT and MDA results. The results confirm that the treatment RsPHGPx can protect of cells via scavenging oxygen.Furthermore, in order to evaluate the joint effects of glutathione and RsPHGPx. Research regarding to the comparation and co-effect of these two reagents was applied. The results show that when minim RsPHGPx was add to the cells, the protect effects of glutitotine can be significantly increased. These results suggest the possibility for use of RsPHGPx as a therapeutic protectant.