Ischemic postconditioning protects skeletal muscle from ischemia/reperfusion injury through improving microcirculation in rat hind limb

AIM:To investigate the effect of ischemic postconditioning(I-postC)on ischemia/reperfusion(I/R)injury of skeletal muscle and its microvasculatory mechanisms in rat hind limb.METHODS:Healthy male Wistar rats were randomly divided into three groups as follows(n=16):I/R group,I-postC group and ischemic preconditioning(IPC)group.I/R of right hind limb was induced by clamping right femoral artery.The effects of I-postC on oxygen saturation of hemoglobin(StO2),blood flow,microcirculation,hemodynamics,Wet/Dry ratio(W/D)and ultramicrostructure of skeletal muscle were detected on 12 h or 24 h after reperfusion.RESULTS:(1)Compared with I/R group,12 h after reperfusion,W/D from I-postC group decreased 6.7%(P0.05)and myofibrillae lysis of skeletal muscle and vacuolation of mitochondria attenuated than that in I/R group.24 h after reperfusion,-dp/dtmax in I-postC group increased 10.46%(P0.05).(2)It was also found that 24 h after reperfusion,blood velocity in venule increased 11.3% in I-postC group compared with that in I/R group(P0.05),and internal diameter of arteriole and venule increased 39.8% and 24.1% compared with that in I/R group,respectively(P0.01).No significant difference between I-postC and IPC groups(P0.05)was found.CONCLUSION:I-postC protects the skeletal muscle against reperfusion injury by improving microcirculation.