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 (StO2), 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% (P<0.05) and myofibrillae lysis of skeletal muscle and vacuolation of mitochondria attenuated than that in I/R group. 24 h after reperfusion,-dp/dtmax in I-postC group increased 10.46% (P<0.05). (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 (P<0.05), and internal diameter of arteriole and venule increased 39.8% and 24.1% compared with that in I/R group, respectively (P<0.01). No significant difference between I-postC and IPC groups (P>0.05) was found. CONCLUSION: I-postC protects the skeletal muscle against reperfusion injury by improving microcirculation.