| Summary: | 碩士 === 中山醫學大學 === 營養科學研究所 === 92 === Abstract
Recent years, cardiovascular disease was one of the ten most common causes of death in Taiwan. The etiology of cardiovascular disease is contributed to a variety of factors, and the long term exposure of inorganic arsenic is one of them. Although the pathologic mechanism of arsenic on cardiovascular disease is unclear, the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) by arsenic is regarded to be one of the possible candidates. Arsenic caused oxidative stress and nitrative stress caused have been demonstrated to affect cell signaling and cell functions. This study was conducted to examine whether arsenic initiated protein carbonylation and nitration in human umbilical vein endothelial cells (HUVECs). By slot blotting analysis, results show that cellular carbonylated protein level increased 1.6-fold and 1.9-fold in HUVECs treated with 0.5 μM sodium arsenite or 2.0 mM hydrogen peroxide, respectively, as compared with control. In addition, 1.0-10 μM sodium arsenite also increased nitrated protein production as comparated with control. We further identified carbonylated proteins by two-dimensional gel electrophoresis and matrix assist laser desorption ionization time of flight mass spectrometery (MALDI-TOF/MS). As indicated, sodium arsenite seems to preferably modify certain proteins, and the patter of protein carbonylation was different from that of hydrogen peroxide. It suggests that arsenic and hydrogen peroxide may have different pathological effects. Followed by the proteomic analysis, two of arsenic-sensitive proteins were identified to be the α-enolase and actin binding protein-Facin. Due to the role of α-enolase on intracellular glycolysis and Facin on the stability of cytoskeleton, it is compelling to examine whether such an oxidative modification on certain proteins contributes to arsenic toxicity.
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