Age-related Alterations of Bcl-2 and Bax Immunoreactivities in the Ischemic-reperfused Tibialis Anterior and Soleus Muscles of the Rats

Seo, Youn Kyoung; Shin, Chae Soo; Kim, Jong Heon; You, Young June; Paik, Doo Jin

Abstract

Prolonged ischemic-reperfusion induces cellular damages and apoptosis in rat skeletal muscle. Reactive oxygen species generated during reperfusion time induce expression of various genes and apoptosis. Among apoptosis-related gene products, Bcl-2 and Bax regulate the apoptotic response by inhibiting and promoting cell death, respectively. The purpose of this study was to observe the age-related alertation of expression profile of Bcl-2 and Bax in rat tibialis anterior muscle and soleus muscle following ischemia-reperfusion. 9 weeks, 30 weeks, and 65 weeks old male Sprague-Dawley rats were divided into control and ischemia groups. Ischemia group was divided into 3 subgroups based on reperfusion time. For ischemia, left commom iliac artery was occulded for 4 hours using rodent vascular clamps. The animals were sacrificed at hours 0, 3 and 24 after onset of reperfusion and tibialis anterior and soleus muscles were removed. Muscle tissues were embedded in paraffin and 6 micrometer sections were made. The expression level of Bcl-2 and Bax were examined using immunohistochemical methods. The results obtained were as follows; 1. In control group, immunoreactivities (IMRs) of Bcl-2 and Bax were weak or moderate in 30 weeks old rats and were trace in 9 and 65 weeks old rat. 2. In control group, IMRs of Bcl-2 and Bax in tibialis anterior muscle were more higher than those in soleus muscle, but not significantly. 3. In ischemia group, IMRs of Bax were increased with aging. 4. In ischemia group, IMR of Bax in tibialis anterior muscle was higher than that in soleus muscle. These results suggested that the increased IMR of Bax may be related to increasing of ischemic injury, and both old skeletal muscle and tibialis anterior muscle are susceptabile to ischemic injury of rat skeletal muscle.