心血管疾病近年來位居台灣十大死因前茅。該疾病為多種原因所造成，無機砷的長期暴露為其中原因，砷造成心臟血管疾病之機轉目前仍不清楚，但砷造成活性氧（ROS）與活性氮（RNS）壓力增高可能是其中機轉之ㄧ。細胞在活性氧與活性氮壓力下，會造成細胞內蛋白質發生氧化及硝基化作用，改變蛋白質功能或影響訊號傳遞，因而改變了血管內皮細胞之生理特性，導致心血管病變。本研究分別以0.5 ~ 40 μM亞砷酸鈉（NaAsO2）、2 mM過氧化氫、1 mM一氧化氮提供者（SIN-1）或0.5 mM過氧硝基（ONOO-）處理人類臍動脈內皮細胞（human umbilical vein endothelial cells），再以狹縫（Slot）、西方墨點法及二維蛋白質電泳分析蛋白質羰基化（carbonylation）及硝基化（nitration）之形成。結果顯示0.5 μM亞砷酸鈉及2 mM過氧化氫處理下，羰基化程度分別為對照組1.6倍及1.9倍；另外1 ~ 10 μM亞砷酸鈉及1 mM SIN-1處理下，蛋白質硝基化程度也均較對照組強。進一步利用二維電泳分析找出形成羰基化的蛋白質，圖譜顯示亞砷酸鈉引起活性氧壓力下，會選擇性的羰基化某些蛋白質，這與過氧化氫全面性的羰基化蛋白質不同，因此，可推測砷與過氧化氫造成之病理效應可能不同。藉由質譜儀進一步分析，發現其中兩個砷敏感性的羰基化蛋白質點，分別為參與醣解作用之酵素α-enolase及肌動蛋白結合蛋白質Fascin，推測砷可能會降低細胞內糖解反應的進行，造成細胞能量不足，因而干擾細胞週期的進行，或者影響纖維蛋白溶解作用造成血栓的發生；Fascin氧化修飾作用可能減少細胞架構穩定性，進而改變細胞形態與完整性。
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.
