Metabolic alterations of skeletal muscle tissue after prolonged acute ischemia and reperfusion

Acute tissue ischemia is usually followed by considerable disturbances of cellular metabolism that often lead to cell death. Reperfusion improves cellular function by withdrawing the toxic products of ischemia and providing energy sources, although sometimes it worsens it. The purpose of this experimental work is to study the metabolic disturbances in skeletal muscle tissue of canines after prolonged acute ischemia in relation to the values of certain substances (ATP, lactate, pyruvate, the ratio of lactate to pyruvate [L/P], and glucose) and whether the alterations in the values of these substances could be used as prognostic indices of the magnitude of tissue damage and the possibility of inverting it. We used 15 mongrel dogs. Complete acute ischemia was induced in the right lower limb lasting 12 h. Reperfusion also lasted for 12 h. The left lower limb was used as reference value. Before the beginning of ischemia, at 1/2, 1, 6, and 12 h after the induction of ischemia, and at 1/2, 1, 6, and 12 h after the restoration of circulation, blood samples, and tissue biopsies were obtained from the healthy and the experimental limb for the measurement of ATP, lactate, pyruvate, the ratio of L/P, and glucose. From the statistical analysis of the values of the controlled parameters the following were concluded: The changes in ATP, lactate, pyruvate, and the L/P ratio in the venous blood of the experimental limb and in the intracellular space of the suffering skeletal muscle could be used as indices to evaluate ischemic injury to the skeletal muscles, the course of its development, and the possibility of reversal after reperfusion.