Effect of different periods of hyperbaric oxygen on ischemia-reperfusion injury of rat skeletal muscle.

The effect of hyperbaric oxygen (HBO) on ischemia-reperfusion injury of skeletal muscle, applied during different periods, was studied in 56 male rats. Animals were subjected to 6-h ischemia by a tourniquet over the major femoral trocanter and 4 (A) or 24 (B) h of reperfusion. HBO was carried out during 1 h in an acrylic chamber at a pressure of 2.0 ATA (100% oxygen): in the last 60 min of ischemia (II), after ischemia, during 1-h reperfusion time (III), and during the last hour of ischemia plus 1-h reperfusion (IV). Group I was the control group. After 4- or 24-h reperfusion, samples of the soleus muscle were stained by H&E and analyzed immunohistochemically. No interstitial hemorrhage, neutrophil infiltrate, or cellular necrosis were induced by HBO. The apoptosis index did not differ among the groups. HBO reduced morphologic alterations and promoted better results when administered in the ischemia plus reperfusion period (GIV).