[The sequential metabolic and histological changes occurring in dog leg muscles as a consequence of ischemia...

The present study was undertaken to investigate the sequential metabolic and histological changes occurring in dog leg muscles as a consequence of ischemia. The left hind limbs of 45 dogs were amputated at the middle of their thighs and after preserving them in ice water and room temperature for 6 and 12 hours, re-circulation was established. Observation was undertaken on 1) activity of muscle enzymes-CPK, GOT-m, and LDH in the venous blood from the re-circulated limbs, and 2) histological changes of muscles through light microscopy and electron microscopy. Leakage of muscle enzymes into the serum was little in the group preserved in ice water for 6 hours, but resulted in a marked increase in the group preserved in room temperature for 6 hours and 12 hours ischemic groups. This remarkable leakage of muscle enzymes seems to reflect the amount of muscle degeneration. Histologically prominent changes of muscles were characterized by cell swelling and separation of sarcoplasma from endomysium through light microscopic study, and by widening of myofibril space, virtual absence of glycogen granules in sarcoplasma, swelling of mitochondria and appearance of intramitochondrial dense body through electron microscopic study. These histological changes of muscles are well correlated with the leakage of muscle enzymes and demonstrated some extent of irreversible changes had developed already, even in the group preserved in ice water for 6 hours.