Abstract
The purpose of the present study was to evaluate the regeneration process in the experimental ischemic myopathy and to elucidate the relationship between the severity of necrotic lesion and vascular distribution. The experiment was conducted on 15 adult cats. Ischemic muscle was prepared by ligation inferior region of abdominal aorta, the right common iliac artery and the right femoral artery for 7 hours simultaneously. The animals were sacrificed on 7th, 10th and 14th days after the surgery, and the lesion of crural muscle was histochemically examined. The result of the experiment were as follows: (1) In the distribution of necrosis of crural muscle, outer surface of the muscle and around the main artery in the muscles were tend to save from necrosis. The necrosis of anterior tibial muscle (hereinafter referred as“Ta”) was distributed segmentally on both proximal and distal sites, while proximal site of medial gastrocnemius muscle (Gm) and soleus muscle (Soleus) were affected by the ischemia. (2) Severity of ischemic changes in each crural muscle group was observed as Ta≥Gm≥Soleus. (3) Distribution of regenerated fibers and its maturation process: After 7 days of ischemia, amorphous myoblast having prominent muscle within the large nucleus, appeared at the boundary areas between necrotic lesion and normal tissues. After 10 days of ischemia, most of the ischemic lesion was occupied by small round muscle fibers having 1/2-1/3 of the diameter compared with that of normal fiber. The more matured regenerated fibers were seen outside, and the myoblast were recognized in the center of necrotic lesion. After 14 days of ischemia, both myoblast and small round muscle fibers were almost disappeared, and the matured regenerated fibers were seen scattered among the normal fissures. They did not differ very much from normal fibers except the central nucleus and disarrangement of intermyofibrillar network. Conclusion: Regeneration process in experimental ischemic myopathy did not show uniform maturation. It's depend on the severity of ischemic damages of the muscles and might be related deeply with blood supply to the ischemic muscles.
