운동강도의 차이가 60주령된 흰쥐의 Soleus와 EDL에서 Bcl-2, Bax, caspase-3와 DNA 절편화에 미치는 영향

Abstract

The purpose of this study was to find out the Bcl-2 (B-cell leukemia/lymphoma-2), Bax, and caspase-3 (cysteine-aspartic proteases-3) protein expression in soleus and EDL muscle according to treadmill ex-ercise intensity in 60 week-old SD rats. The SD rats were randomly divided into four groups (n=10 in each group): control (CON), low intensity exercise (LE), moderate intensity exercise (ME), and high intensity exercise (HE). The exercise was given to the rats for 8 wk, 5 day/wk. The animals under-went treadmill exercise at intensities of 30 min at 8 m/min for the LE group, 15 min at 16 m/min for the ME group, and 9 min at 24 m/min for the HE group. The results were as follows: the ex-pression of Bcl-2 protein was lowest in the HE group and the expression of Bax protein was highest in the HE group. The expression of caspase-3 (cleaved form) protein was observed in the HE group. For the different types of muscle fiber, Bcl-2 protein expression in the soleus muscle was decreased in all groups. Bax protein expression in the soleus muscle was increased in the HE group only. Bcl-2 protein expression in the EDL muscle was decreased in the HE group, and Bax protein expression in the EDL muscle was increased in the ME and HE groups. Consequently, the protein expression related to the aged rats shows a difference according to the intensity of exercise. In addition, caspase-3 protein expression appeared in the HE group; however, in all amounts of intensity, DNA fragmenta-tion was not observed. Therefore, apoptosis on skeletal muscles of aged mice can be intervened with optimal exercise. On the other hand, high intensity exercise can potentially accelerate the apoptosis of muscle fiber in aged rats. Keywords : Exercise intensity, apoptosis, Bcl-2, Bax, caspase-3