Serial morphological changes in primate skeletal myofibres after 3 hours of ischaemia and 24 hours of reperfusion.

The sequential morphological changes occurring in skeletal myofibres after 3 hours' ischaemia and from 3 hours to 24 hours of reperfusion in vervet monkeys are described. Eight vervet monkeys were studied under general anaesthesia. A hind limb was exsanguinated and a tourniquet applied for 3 hours. Open muscle biopsy specimens were obtained from the tibialis anterior muscle before tourniquet application, just before tourniquet release and 3, 6, 12, 18 and 24 hours after tourniquet deflation. All specimens were prepared for transmission electron microscopy. After 3 hours of ischaemia and increasing periods of reperfusion, a small number of fibres showed progressive pathomorphological changes that eventually resulted in myofibre death. After initial glycogen loss and later intermyofibrillar oedema, the majority of myofibres returned to normal, while a group of fibres remained oedematous. The progressive morphological characteristics of reversibly injured myofibres undergoing repair and irreversible injured cells undergoing necrosis are described.