單次離心運動對骨骼肌粒腺體釋出細胞色素C及細胞凋亡誘發因子的影響

The effect of single bout eccentric exercise on mitochondria released cytochrome c and apoptosis inducing factor in skeletal muscle

"目的：探討離心運動對骨骼肌粒腺體釋出細胞色素c（cytochrome c，cyt-c）及細胞凋亡誘發因子（apoptosis inducing factor，AIF）的影響。方法：以8週齡雄鼠（Sprague-Dawley）為本研究之受試對象，將實驗動物隨機分成控制組（control；N＝4）、運動控制組（level running，LR；N＝16）及離心運動組（downhill running，DHR；N＝16）。LR（坡度0度）及DHR（坡度-16度）之實驗動物於動物跑步機上以20m／min之速度跑步90分鐘，每回合跑5分鐘休息2分，共計18回合。LR與DHR分別於運動後第0（n＝4），24（n＝4），48（n＝4）及72（n＝4）小時將實驗動物犧牲，取出前肢肱三頭肌（tricepsbrachiimuscle）進行後續分析。結果：DHR在運動後第0小時之活化的c-Jun氨基末端激酶（phosphorylated c-Jun NH2-terminal kinase）表現量高於LR（p＜.05）。運動後第24及48小時之DHR粒腺體釋出cyt-c至細胞質的表現量高於LR（p＜.05）。LR及DHR對粒腺體釋出AIF至細胞質的表現量均無顯著差異（p＞.05），但DHR在運動後第24小時細胞核核內AIF表現量高於LR（p＜.05）。結論：（一）在運動後第24及48小時，單次之離心運動會增加骨骼肌粒腺體釋出細胞色素c至細胞質的表現量。（二）單次之離心運動不會影響骨骼肌粒腺體釋出AIF至細胞質的表現量，但在運動後第24小時具有增加細胞核核內AIF表現量的現象。Purpose: This study was to investigate the effect of eccentric exercise on mitochondria to release the cytochrome c (cyt-c) and apoptosis inducing factor (AIF) in skeletal muscle. Methods: Animals, male Sprague-Dawley rats, were randomly assigned to either a rest control group (N=4), an exercise control group (level running, LR; N=16) or an eccentric exercise group (downhill running, DHR; N=16). The rats in both LR and DHR ran on animal treadmill at a constant speed of 20 m/min on the level (0 degree incline) or downhill (a 16 degree decline) for 90 min. The 90 min running time was divided into 5 min runs separated by 2 min rest intervals (18 bouts). Rats were sacrificed at post-exercise 0 hour (PE0; n=4), post-exercise 24 hours (PE24; n=4), post-exercise 48 hours (PE48; n=4) and post-exercise 72 hours (PE72; n=4), respectively. The triceps brachii (TB) muscle was dissected out and frozen in liquid nitrogen rapidly. Results: The phosphorylated c-Jun NH2-terminal kinase (p-JNK) expression of DHR was significantly higher than LR at PE0 (p < .05). The expression level of cytosolic cyt-c released from mitochondria of DHR which was significantly higher than LR at both PE24 and PE48 (p < .05). The expression level of nuclei AIF of DHR was significantly higher than LR at PE24 (p < .05). Conclusions: 1) A single bout eccentric exercise might increase the expression level of cytosolic cyt-c released from mitochondria in TB at both PE24 and PE48. 2) A single bout eccentric exercise didn't affect the expression level of cytosolic AIF released from mitochondria in TB. However, the expression level of nuclei AIF was increased at PE24 after a single bout eccentric exercise."