Isolated perfusion of a tubed superficial epigastric flap in a rodent model

BACKGROUND: Isolated perfusion models can yield important data regarding metabolism of the skin. An effective model must remain stable during perfusion but respond appropriately to metabolic and vascular stimuli. We describe the design and characterization of a tubed superficial epigastric isolated perfusion flap. MATERIALS AND METHODS: Tubed superficial epigastric flaps were created in 20 male Sprague Dawley rats. Forty-eight hours later the femoral vessels were cannulated and the flaps were perfused using a Krebs-Heinseleit buffer containing albumin for a period of 2 h. In five of the flaps norepinephrine and acetylcholine were added sequentially to the perfusate to determine vascular reactivity. In a further four flaps insulin (20 U/liter) and iodoacetate (5 mM) were added to the perfusate to confirm that the flap was metabolically active and reactive. Venous outflow was collected at regular intervals and analyzed for electrolytes, lactate, and glucose content. Vascularity and skin perfusion were characterized using barium microangiography and methylene blue dye injection. RESULTS: This flap model was found to be stable in terms of arterial pressure, electrolyte levels, and lactate production over the perfusion period. Norepinephrine caused a sharp increase in vascular resistance, which was reversed by administration of acetylcholine. Lactate production increased appropriately with the addition of insulin to the perfusate with a rapid decline following addition of the glycolysis inhibitor iodoacetate. There was no leakage of perfusate or significant swelling of the flap during the perfusion. CONCLUSIONS: The tubed superficial epigastric artery flap makes an effective model for isolated perfusion studies of the skin with a wide range of experimental applications.