高強度間歇式運動對肌腱熱休克蛋白表現之影響

高強度間歇訓練 (High Intensity Interval Training，HIIT) 具備快速增進骨骼肌有氧代謝的效果，對於代謝症候群 (metabolic syndrome) 的預防與治療提供有效的運動介入模式。高強度的運動易造成骨骼、肌肉、肌腱、與靭帶的過度使用，是否 HIIT 會造成這些組織的傷害，目前尚無相關的研究。細胞在高溫、自由基堆積、營養失衡、與缺氧的情形下，會產生熱休克蛋白 (heat shock proteins，HSP) 進行防禦與修復的機制，因此科學研究經常以 HSP 的大量表現情形，做為細胞壓力的生化指標。本實驗的研究目的在探討 HIIT 是否對大白鼠的阿基里斯肌腱造成細胞壓力，進而評估服用抗氧化劑對減緩此細胞壓力的效果。將雄性大白鼠分為控制組 (C)；HIIT 組 (H)；維生素 C 控制組(CV)；維生素 C 進行 HIIT 組 (HV)。每日餵食維生素 C 達 7 日後，大白鼠即進行 14 日的 HIIT，訓練期間持續餵食維生素 C，總計 21 日。完成訓練後進行走秀試驗 (Catwalk test) 以分析其步態，再取出阿基里斯肌腱進行蛋白質電泳分析其 HSP 的表現量。結果顯示 HIIT 後大白鼠的步態工作因子(duty factor) 比控制組低，加上HIIT 組大白鼠 on toe 的步態方式，均指向 HIIT 造成步態改變。阿基里斯肌腱內的 HSP27 和 HSP70 表現量較控制組顯著增加。服用維生素 C 進行 HIIT 組的步態分析與 HSP 表現量無異於控制組。此外，免疫組織螢光染色亦發現 HIIT 組有最多的 HSP70 反應，服用維生素 C 進行 HIIT 組的 HSP70 反應程度顯著減少。此實驗結果顯示 HIIT 會造成動作協調性的異常，進而造成阿基里斯肌腱的損傷或是形成功能上的進步仍難以確定。此現象與自由基生成有關，畢竟服用維生素 C 能夠減少 HSP 的表現量與恢復動作協調性。

關鍵字

高強度間歇訓練；維生素C ；阿基里斯肌腱；熱休克蛋白

並列摘要

The effect of High-Intensity Interval Training (HIIT) on the Achilles tendon is not completely understood. Heat shock protein (HSP) is produced by acute exercise-induced radical oxygen species (ROS) in humans, upregulated in heat shock response, an indicator of cellular stress, acting as chaperone protein and stabilizing new protein or help-ing to refold impaired protein. We hypothesized that supplementation of Vitamin C in HIIT may modulate the gait and expression of HSPs & IGF-1 (insulin-like growth factor 1) in Achilles tendon. Twenty-eight male Sprague-Dawley male rats were randomly divided into the fol-lowing four groups including control (C, n=7), HIIT (H, n=7), control  Vitamin C (CV, n=7), HIIT  Vitamin C (HV, n=7). The amount of Vitamin C was 500mg/kg/day for 3 weeks in the CV and HV groups. The H & HV groups received HIIT by treadmill for 2 weeks. Statistical significance was set at p<0.05. Hindlimb footprints of the H group re-vealed on-toe pattern. The parameters of Cat-Walk test, including swing duration, step cycle, duty factor and step length, were signifi-cantly different in groups (p<0.05). Comparing HV to H, only swing duration showed significance (p<0.05). HSP27, HSP70 and IGF-1 of the Achilles tendon expressed elevation in the H group (p<0.05), but remained near to basal level in the HV group (p<0.05). Immunofluo-rescent analysis of HSP70 in the Achilles tendon showed positive cy-toplasmic localization in many cells of the H group, but only in a few cells of the HV group. H group showed decreased duty factor and on-toe gait of locomotion indicating the alteration of gait compared to control. H group showed dramatically increased HSP70 and HSP27 in Achilles tendon indicating the possibility of cellular stress after HIIT. After Vitamin C consumption, the supposed dramatic increasing ex-pression of HSPs in H group has been diminished indicating the im-portant role of ROS in HSP induction during HIIT. The increased IGF-1 secretion in H group contributed to protein synthesis in Achilles tendon indicating adaptation of tendon after HIIT. After vitamin C consumption, the supposed dramatic increasing secretion of IGF-1 in H group has been diminished indicating the important role of ROS in IGF-1 secretion during HIIT. HIIT causes adaptation in the Achilles tendon. Whether HIIT causes Achilles tendon impairment or functional improvement is uncertain according to the alteration of gait. Imbalance between production and clearance of ROS can be withstood by Vita-min C supplementation.