| 摘要: | 電銲作業者可能因電銲作業過程中產出的金屬燻煙，而較非電銲作業者容易暴露在大量活性氧物種所造成的高氧化壓力環境中。研究顯示維生素B-6可能直接清除自由基或藉由擔任從同半胱胺酸代謝成胱胺酸再到麩胱甘?的合成過程中的輔?而間接扮演抗氧化功能的角色。此外，高同半胱胺酸被認為會增加氧化壓力及降低麩胱甘?依賴的抗氧化酵素活性。因此本研究目的是評估有無參與電銲作業者其維生素B-6營養狀況（血漿及紅血球磷酸比哆醛濃度）及同半胱胺酸濃度與氧化壓力及抗氧化能力間的相關性。本橫斷式研究共募集到71位健康器材製造工廠的受試者，依照有無暴露於金屬燻煙環境，分成暴露組（n = 29）及未暴露組（n = 42）。抽取受試者的空腹血液以檢測維生素B-6營養狀況（血漿與紅血球磷酸比哆醛濃度及血漿比哆酸）、氧化壓力指標 (包括血漿同半胱胺酸、血漿丙二醛、血漿氧化型低密度脂蛋白及尿液8-羥基-2'-去氧鳥糞嘌呤)、抗氧化能力 (包括血漿總抗氧化能力)、紅血球麩胱甘?濃度及抗氧化酵素活性 (包括紅血球超氧化歧化?、麩胱甘?硫轉移?及麩胱甘?過氧化?) 。結果顯示暴露組及非暴露組皆有充足的維生素 B-6（血漿磷酸比哆醛 > 20 nmol/L），兩組間的血漿及紅血球磷酸比哆醛濃度無顯著差異。暴露組的氧化型低密度脂蛋白濃度顯著高於未暴露組，而暴露組的紅血球麩胱甘?濃度、紅血球超氧化物歧化?活性及紅血球麩胱甘?硫轉移?活性顯著低於未暴露組。暴露組血漿及血球磷酸比哆醛濃度與血漿同半胱胺酸濃度呈顯著負相關。暴露組的血漿PLP與血漿總抗氧化能力呈正相關 (rs = 0.43, p < 0.05)，而未暴露組則是紅血球磷酸比哆醛與紅血球超氧化物歧化?(rs = 0.40, p < 0.0)及麩胱甘?過氧化?(rs = 0.34, p < 0.05)酵素活性呈正相關。暴露組血漿同半胱胺酸濃度在調整相關干擾因子後對紅血球麩胱甘?濃度(β = 0.05, p < 0.05)及紅血球超氧化物歧化?活性(β = 250.05, p < 0.05)呈顯著影響。當電銲作業者的維生素B-6 營養狀況充足時，高同半胱胺酸濃度是影響抗氧化酵素活性的重要因子。
Welding is a process of joining metals by melting and fusing and would generate fumes which contain many metals and toxic gases. During the process of welding, the potential exposures of these materials to welders would be associated with increased oxidative stress and alterations in antioxidants or antioxidant enzyme ativities when compared to controls. Vitamin B-6 (pyridoxal 5’-phosphate, PLP) has been shown to may directly scavenge radicals and lipid peroxidation, or may indirectly play the role of antioxidant through serving as coenzymes in the homocysteine metabolism to cysteine and further to glutathione. In addition, elevated homocysteine concentration has been fouced to cause greater oxidative stress and decreased glutathione-related antioxidant defence system. Therefore, the purpose of this cross-sectional study was to examine the association of vitamin B-6 status (plasma and erythrocyte PLP) and homocysteine with oxidative stress and antioxidant enzyme capacities in welders. Seventy-one workers were divided into either exposure (n=29) or non-exprosure (n=42) groups based on whether they engaged in the welding process. The levels of fasting vitamin B-6 status (plasma erythrocyte PLP, plasma 4-pyridoxic acid), oxidative stress indicators [i.e., plasma homocysteine, plasma malondialdehyde (MDA), oxidized low density lipoprotein (ox-LDL) and urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG)], antioxidant capacity [total antioxidant capacity (TAC) and erythrocyte glutathione] and antioxidant enzyme activities [i.e., erythrocyte superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione peroxidase (GPx)] were determined. There were no significant differences in vitamin B-6 status between exposure and non-exposure group, and both groups had adequate vitamin B-6 status (plasma PLP > 20 nmol/L). Exposure welders had significantly higher levels of ox-LDL and lower erythrocyte glutathione, SOD and GST when compared to non-exposure workers. Plasma and erythrocyte PLP concentrations were significantly negatively correlated with plasma homocysteine in exposure welders. Plasma PLP was positively correlated with total antioxidant capacity in exposure welders (rs = 0.43, p < 0.05), while erythrocyte PLP was positively associated with SOD (rs = 0.40, p < 0.01) and GPx (rs = 0.34, p < 0.05) activities in non-exposure controls. Plasma homocysteine significantly correlated with erythrocyte GSH concentration (β = 0.05, p < 0.05) and erythrocyte SOD activity (β = 250.05, p < 0.05) after adjusting for potential confounders in exposure welders. Elevated plasma homocysteine seemed to be a major contributing factor to increased oxidative stress and antioxidant enzyme activity in welders. |
