Attenuation of vasospasm and capillary no-reflow by ischemic preconditioning in skeletal muscle

Vasospasm and capillary no-reflow are common complications following replantation and free flap transfer. The purpose of the present study was to clarify whether vasospasm and capillary no-reflow which are induced by prolonged warm ischemia/reperfusion can be attenuated by ischemic preconditioning in the vascular isolated cremaster muscle model. Male Sprague-Dawley rats were anesthetized with pentobarbital. Arteriole diameter and capillary perfusion were measured utilizing intravital microscopy. In the control group, the cremasters sustained 4-hour warm global ischemia followed by 60-minute reperfusion. In the ischemic preconditioning group, the cremasters were subjected to one cycle of 45-minute ischemia followed by 15-minute reperfusion prior to 4-hour warm global ischemia followed by 60-minute reperfusion. The results from this experiment showed that ischemic preconditioning significantly attenuated ischemia/reperfusion-induced vasospasm and capillary no-reflow which occur early during reperfusion after prolonged warm ischemia in skeletal muscle. The mechanism of this phenomenon remains to be elucidated.