Arterial blood flow and microcirculatory changes in the rat groin flap after ischemia provocation by electrical stimulation of the artery.

An island groin flap based on the inferior epigastric vessels was raised in 10 rats in order to monitor simultaneous ischemic changes in arterial blood flow and skin microcirculation induced by electrical stimulation of the feeding artery. A modified laser Doppler perfusion system recorded blood flow in the epigastric artery and in the skin microcirculation of the flap before and for 40 min after the experimentally induced ischemia. Sections of the stimulated segment of the vessel were obtained at the end of the experimental procedure for histological analysis to determine the extent of endothelial changes, if any. Artery blood flow and the flap microcirculation decreased significantly immediately after stimulation, both slowly increasing to prestimulation levels after 30 min. Artery perfusion was quicker than microcirculation to recover to the baseline value, indicating that reperfusion of larger vessels could involve mechanisms fundamentally different from those active in the resolution of ischemia at the capillary level. Histological artery examination revealed no significant endothelial damage at the stimulation site, thus demonstrating that electrical stimulation induces reproducible ischemia without visible endothelial damage. The differential effects on the feeding artery and on capillary perfusion indicate recruitment of several different mechanisms.