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 bloo d flow and skin microcirculation induced by electrical stimulation of the f eeding artery. A modified laser Doppler perfusion system recorded blood flo w in the epigastric artery and in the skin microcirculation of the flap bef ore and for 40 min after the experimentally induced ischemia. Sections of t he stimulated segment of the vessel were obtained at the end of the experim ental procedure for histological analysis to determine the extent of endoth elial changes, if any. Artery blood flow and the flap microcirculation decr eased significantly immediately after stimulation, both slowly increasing t o prestimulation levels after 30 min. Artery perfusion was quicker than mic rocirculation to recover to the baseline value, indicating that reperfusion of larger vessels could involve mechanisms fundamentally different from th ose active in the resolution of ischemia at the capillary level. Histologic al artery examination revealed no significant endothelial damage at the sti mulation site, thus demonstrating that electrical stimulation induces repro ducible ischemia without visible endothelial damage. The differential effec ts on the feeding artery and on capillary perfusion indicate recruitment of several different mechanisms. (C) 2001 Academic Press.