Ultrastructural Changes in Striated Muscle after Experimental Tourniquet Ischaemia and Short Reflow

Abstract

The effect of experimental tourniquet ischaemia on the fine structure of a rabbit’s hind limb striated muscle was studied. The tourniquet time varied from 1 to 4 h. Samples were obtained from the tibialis anterior muscle 30 min after releasing the tourniquet, the contralateral limb serving as the control. As the first sign of ischaemia, dilatation of the sarcoplasmic reticulum was observed after a tourniquet blockade of 1 h. After 4 h ischaemia myofibrillar components showed advanced degeneration. Ultrastructural alterations were distinct in the mitochondral morphology. After 2 h, the mitochondria showed moderate but clear condensation. After 3 h many mitochondria showed high amplitude swelling and structural disorganization. Total blockade of the limb circulation up to 4 h effects the energy-producing organelles in the first place, especially sarcoplasmic reticulum, T tubules and mitochondria prior to the alterations in myofilaments. Ischaemia extended up to 3 h induces sublethal damage to the muscle cells.

Morphological and biochemical changes in striated muscle after experimental tourniquet ischaemia

“…The present findings on the succinic dehydrogenase and lactic dehydrogenase activities are consistent with our previous fine structural findings [15] and support the findings recently reported by Tountas et al [18]. As estimated from the SDH activity, the mitochondria in striated muscle seem to tolerate three-h and four-h ischaemia well since these activities did not significantly differ from the control values after 30 min and 24 h reflow.…”

“…As estimated from the SDH activity, the mitochondria in striated muscle seem to tolerate three-h and four-h ischaemia well since these activities did not significantly differ from the control values after 30 min and 24 h reflow. In the previous ultrastructural study [ 15] it was seen that many mitochondria were either condensed or highly swollen after three-h ischaemia followed by 30min reflow. However, it would appear that these structural changes do not impair the SDH enzyme function significantly or perhaps the number of highly swollen mitochondria is too small to affect total SDH activity values.…”

“…Recently, we described the fine structural changes observed in striated muscle after one to four h experimental tourniquet ischaemia followed by 30 min reflow [15]. The purpose of the present study was to analyse the tissue concentrations of lactic dehydrogenase (LDH) and succinic dehydrogenase (SDH) in striated muscle tissue subjected to e x p e r i m e n t a l t o u r n i q u e t ischaemia and to c o m p a r e the results with the m o r p h o l o g i c a l changes o b s e r v e d u n d e r those conditions.…”

Effect of Tourniquet Ischaemia on Carbohydrate Metabolism of Dog Skeletal Muscle

“…Morphological changes in striated muscle [6,24,27] and release of intracellular inter mediates to the extracellular space are con sidered to be one of the early signs of isch aemic cell injury [8,9,16]. Muscle lactate level increases during complete tourniquet ischaemia of human and dog skeletal muscle [8,9], In the present study, muscle lactate concentration was significantly elevated dur ing tourniquet ischaemia and, in the normal range, 1 h after recirculation (table III).…”

“…However, com plete arrest of the circulation to the limbs produces acidosis and changes in the level of potassium [28. 32], After long-lasting blood flow interruption to a dog extremity there was a rapid decrease in muscle phosphocreatine, ATP and tissue pH, whereas the muscle lactate concentration was markedly elevated [29], Studies on the fine structure of the striated muscle in the hind limb demon strated ultrastructural changes of the energyproducing organelles and advanced degener ation of myofibrillar components after 4 h of ischaemia [24], Therefore, in clinical prac tice, it is evident that the duration of isch aemia should be as short as possible.…”