低氧預處理對運動後血液氧化壓力的影響

Abstract

預處理 (preconditioning) 定義為在主要的刺激前，先給與短暫或較小的刺激，啟動細胞或組織的保護機制，減低主要刺激帶來的傷害。預處理的方式包含缺血、運動或低氧預處理等，多用於心臟等其他器官組織，少有針對血液與抗氧化能力做探究。低氧刺激與高強度運動皆可增加氧化傷害，藉由兩者的結合，擬探討低氧刺激所啟動的抗氧化機制可否減緩高強度運動對人體帶來的氧化傷害。目的：探討人體在進行高強度運動前，低氧預處理對血液氧化壓力的影響並觀察其對運動後恢復期的變化。方法：徵選19至20歲健康、有規律運動習慣的男性大學生12位，依雙盲重複量數平衡次序法進行低氧預處理及無預處理。低氧預處理：實驗參與者先間斷性吸入相當於海拔5,700m低氧氣體5分鐘再中斷5分鐘，連續進行3個循環 (共30分鐘)，休息1小時後再進行以85% VO2max為固定運動強度的原地跑步機運動30分鐘。常氧控制：與前面處理相同，只需將低氧以常氧氣體替換。於實驗前、預處理後立即、運動後立即、30分鐘、1小時及2小時進行採血，分析抗氧化酶活性與氧化傷害指標。結果：不論有無低氧預處理介入血糖與乳酸在運動後立即顯著升高 (p<.05)。抗氧化方面，預處理的介入對紅血球/血漿超氧離子歧化酶 (SOD)活性、過氧化氫酶 (CAT)活性、麩胱甘肽過氧化酶 (GPx)活性均未達統計上差異。氧化傷害指標方面，紅血球脂質過氧化物 (TBARS) 在運動後立即明顯增加 (p<.05)；低氧預處理運動後立即、30、60分鐘顯著上升(p<.05)。結論：低氧預處理並不能減少中高強度運動所產生氧化傷害，且也不利於人體在高強度運動後的快速復元。

Purpose: To test the hypothesis that levels of erythrocyte antioxidants might increase after hypoxia which may counteract the exercise induced free radicals. Methods: Twelve health college male subjects performed hypoxic precondition (HP) and control (CON) trials with balanced order. HP: Subjects were preconditioned with three 5 min simulated hypoxia (O2=10.3%), each separated by 5 min of normoxia (O2=20.93%). CON: Same as HP but hypoxia was replaced by normoxia. Both trials rest for 1hr then followed with a 30 min of 85% VO2max exercise. Venous blood samples were taken before, post preconditioning and post exercise at 0, 30, 60, and 120 min. Oxidative stress index such as antioxidant enzymes and oxidative damage markers were determined. Comparisons between trails and time points were performed with repeated two-way ANOVA (SPSS 13.0) statistical software. The significant level was set at α<.05. Results: Erythrocyte and plasma antioxidant capacity were not change between HP and CON. Lipid oxidative marker (TBARS) level after exercise was significant higher than at rest (p<.05) in both HP and CON. In HP, the level of TBARS were still significantly higher at 30 and 60 min post exercise. Conclusion: Hypoxic preconditioning cannot lower the oxidative stress induced by exercise and might also prolong the oxidative stress recovery after exercise.