Publication:

長時間單車活動對骨骼代謝之影響

臺灣騎乘自行車人口大幅成長，長時間單車運動有助於增加與維持強壯的肌肉，並可增加心肺功能和血液循環，但對於骨骼的影響目前尚未瞭解。若是透過檢測骨質生化指標或荷爾蒙指標之改變，以觀察骨骼代謝與調控的效果，可迅速地檢測出長時間單車活動對於骨質代謝的影響。本研究目的為探討長時間多天期單車環島活動對於骨週轉率之影響，以及骨骼代謝影響是否產生適應現象，是否為荷爾蒙或骨調控蛋白之sRANKL與OPG來影響骨骼代謝作用。本研究自2008年「鐵駱駝單車環島生活體驗隊」招募受試者32名（24名男性，8名女性），完成單車環島活動共計15天1100公里，受試者與參與此活動前皆無規律地運動習慣，且環島期間受試者攝取各種食物與水分不予限制。血液樣本採集分別在環島活動第一天、第五天、第十天、第十五天和環島活動後第五天。分析血漿OPG與sRANKL使用酵素連結免疫吸附法，分析血漿PTH、Testosterone、Cortisol、tPINP、Beta-crosslaps和Osteocalcin使用電化學發光免疫分析法，分析Serum B-ALP使用自動生化分析儀。結果顯示PTH在環島出發後緩慢地增加，在第十五天時達到最高峰值。Testosterone在環島第五天顯著減少，在第十天後恢復至出發前水平。Cortisol在環島活動期間無顯著變化。OPG在環島活動期間顯著增加；sRANKL則在環島活動期間顯著減少。tPINP在環島第五天顯著減少，在第十天恢復至出發前水平，然而在第十五天則顯著增加。Beta-crosslaps在環島活動第五天顯著減少，在第十天恢復至出發前水平。Osteocalcin在環島活動第五天顯著減少，在第十天恢復至出發前水平。B-ALP在環島活動期間皆顯著減少。本研究最主要發現為未受訓練者在從事單車環島活動中骨質代謝產生明顯的適應現象，可能透過sRANKL/OPG系統來調節骨骼代謝作用，未受訓練受試者從事長時間單車活動時，影響體內荷爾蒙之Testosterone濃度的增加，並藉此調控骨骼調控蛋白之sRANKL/OPG比值，進而影響整體骨質代謝之變化。

Multi-day cycling events had gaining popular among recreational riders in Taiwan. The adaptation effect on bone metabolism has previously reported but mechanisms remain uncertain. The purpose of this study is to reveal the possible dominate factor of bone metabolism changes during a multi-day cycling event. Thirty previous untrained healthy subjects（24 males and 8 females, 19-38 years old）were recruited form participants of 2008 cycling tour of Taiwan. The tour covered approximately 1100 km in 15 days. Fasting blood samples were collected in the early morning on day 1, 5, 10, 15 during the tour and 5 days after the tour. Plasma OPG, sRANKL level was analyzed by ELISA, and PTH, Testosterone, Cortisol, Total PINP, Beta-crosslaps, and Osteocalcin were determined by electrochemiluminescence immunoassay, respectively. Serum Bone-specific alkaline phosphatase were determined by HITACHI-7020 automatic analyzer. PTH level were slightly increased on day 10 and were significantly on day 15. Testosterone level were decreased on day 5 and returned to basal level since day 10. Cortisol level were not significantly changed through out the journey. OPG level were significantly higher compared with basal level. sRANKL level were reduced through the journey. Total P1NP level were reduced on day 5 but returned to basal level on day 10 and significantly higher than basal level on day 15. Beta-crosslaps were reduced on day 5 and then returned to basal level after day 10. Osteocalcin level were reduced on day 5 and then returned to basal level after day 10. Bone-specific alkaline phosphatase level were significantly reduced through out the journey compared to basal level. Results of current study suggested that multi-day cycling tour induced significant adaptation effect which mediated through sRANKL/OPG transduction pathway on bone metabolism. Down-regulation of OPG expression by increased Testosterone level under prolonged exercise stimulation may possibly responsible for the adaption effect of bone metabolism on untrained subjects.