Morphological and biochemical changes in striated muscle after experimental tourniquet ischaemia.

Histological and biochemical changes were studied in the striated muscle following total tourniquet ischaemia between one and four h, the reflow time being 30 min and 24 h. Electronmicroscopy was applied to study the fine structure of the muscle after 24 h reflow. In light microscopy ischaemic changes were not seen even when the tourniquet time was extended to four h. When a four-h ischaemia was followed by a 24-h recovery period, the electron microscopy showed a variety of minor mitochondrial changes such as condensed and slightly dilatated mitochondria. The SDH activities did not vary significantly between the experimental and control samples even after a four-h ischaemia followed by 30 min or 24h reflow. The differences between the experimental and control samples were, however, highly significant in the LDH values in the groups where ischaemia had lasted for three and four h. The results indicate that tourniquet ischaemia for two to three h does not significantly affect the striated muscle of a rabbit and the alterations even after a four-h ischaemia seem to be partly reversible.