Muscle metabolic changes in induced subtotal ischemia of the leg in a pig model

In nine pigs the arterial blood flow to one hind leg was reduced to 5% of resting values during 8 hours in order to study changes in muscle energy metabolism. Biopsy samples from the gastrocnemius muscle were analyzed for ATP, ADP, AMP, PC, Cr, lactate, pyruvate, glycogen and pH before ischemia, at the end of the ischemic period and during 2.5 hours of reperfusion. During ischemia ATP/TCr decreased to 25%, ECP to 80% and PC/TCr to 6% of preischemic values. Lactate increased eightfold and glycogen fell to 40%. In the reperfusion period, lactate decreased to 1/3 of the end-ischemic value, PC/TCr showed threefold rise and ATP/Cr doubled. TCr fell to 66% of preischemic value. Other changes were not significantly affected by reperfusion. The end-ischemic values indicated severe ischemia, but some improvement of metabolism occurred during early reperfusion. The pig model is suitable for further studies aiming to improve the energy state of the cells during ischemia.