Influence of minoxidil on ischemic cutaneous flaps in rats.

Abstract

PURPOSE: To evaluate the influence of minoxidil, a well known vasodilator, on ischemic flap necrosis prevention in rats. METHODS: Ventral cutaneous flaps, measuring 8x4 cm, were designed in 20 Wistar rats based on the right cranial epigastric artery. In the experiment group, 50 mg/kg/day of minoxidil sulfate was administered by orogastric tube and the same amount of saline solution was administered to the control group. Such procedure was initiated 24 h before surgery and kept once a day through the 7th postoperative day. Microcirculation was evaluated with laser fluxometry 24 h before surgical procedure, at immediate postoperative and at the 7th postoperative day. Flap necrosis area was evaluated by 2 methods: planimetry and weight/paper ratio. RESULTS: A significant flow increase in distal and medial extremity at M1 (medial point 1) (p=0.0484) was observed in the experiment group. There was significant difference in flap necrosis prevention in the experiment group (p=0.0433), although after necrosis took place there was no significant difference in necrosis size. (p=0.1051 and p=0.2799). CONCLUSION: Minoxidil sulfate is effective in avoiding necrosis in ischemic flaps, but after necrosis is present there is no difference in survival area between experimental and control groups.