FREE-RADICAL INJURY IN SKELETAL-MUSCLE ISCHEMIA AND REPERFUSION

This study was made in a canine isolated gracilis muscle model to measure directly the free radicals, to predict the severity of ischemia and reperfusion injury of the skeletal muscle by measuring its surface pH (mspH), and to determine the effect of Coenzyme Q10 (CoQ10) in reducing the extent of muscle injury. Animals were divided into three groups: group A (control, n = 10), group B (untreated, n = 10), and group C (CoQ10 treated, n = 10). In both groups B and C, 5 hr ischemia followed by 40 min of reperfusion was made. Free radicals were measured directly by electron spin resonance spectrometer (ESR) and mspH was measured using a pH microprobe. Serum creatine phosphokinase (CPK) was estimated before ischemia, 5 and 30 min after reperfusion. The extent of muscle injury was evaluated morphologically by Evan's blue dye exclusion test. ESR intensity in group B was 0.55 ± 0.19 and decreased to 0.30 ± 0.04 in group C (P < 0.01). Rate of recovery of mspH was higher in group C (7.16 ± 0.06) compared to group B (6.88 ± 0.11, P < 0.01) and CPK in group C was less (847 ± 381 IU/liter) than in group B (1356 ± 519 IU/liter, P < 0.05) after 30 min of reperfusion. In group C the morphological muscle injury was less (37.8 ± 5%) compared to group B (56.7 ± 3.6%, P < 0.01). Linear correlations between the morphological severity of muscle injury and ESR intensity (R = 0.8757, P < 0.001) and mspH (R = -0.8317, P < 0.01) and between ESR intensity and mspH (R = 0.7106, P < 0.001) were observed. In conclusion, free radicals play a great role in the ischemia and reperfusion injury of the skeletal muscle and CoQ10 can reduce the extent of injury. Severity of the muscle injury can be predicted by mspH measurement. © 1991.