The Effect of Melatonin on the Random Flap Survival in the Rat

ABSTRACT

PURPOSE: In skin flap surgery, surgeons often encounter distal ischemia of the flap. If a powerful free radical scavenger is used, it may reduce the formation of free radical and improves the survival of flap. Thus, the present study purposed to examine whether the survival of flap can be enhanced by administering melatonin, which is known to be a powerful free radical scavenger a antioxidant molecule. METHODS: We divided 40 Sprague-Dawley rats into 4 groups, 10 in each group. For the control group(n=10), we intraperitoneally injected only carrier solution once 30 minutes before the operation, and once a day for 7 days from the day of operation. Among the experimental groups, a group(n=10) was administered with dimethyl sulfoxide(DMSO), in another group(n=10), melatonin was intraperitoneally injected, and in the other(n=10) melatonin was intraperitoneally injected and applied topically(2cc of 1% melatonin) to the operation site. Caudally based skin flaps measuring 3x10cm2 were elevated on the mid-dorsum of the rats. and then repositioned. On the seventh postoperative day, the survival area of the flap was measured and tissues were examined under the light microscope. RESULTS: The control group, the DMSO group, the melatonin administration group and the melatonin administration and application group showed the mean survival rates of 55.26+/-9.2%, 70.29+/-7.47%, 81.45+/-4.14% and 86.1+/-1.52%, respectively, for 30cm2 of flap. Compared to the control group, the experimental groups showed a significantly high increase in survival area at significance level of 95%. CONCLUSION: In this study, the survival rate of flap was enhanced through the administration of melatonin after flap surgery. This suggests that melatonin not only functions as a powerful free radical scavenger and oxygen radical scavenger but also stabilizes and protects cells, and by doing so, enhances the survival of moderately injured ischemic sites in the distal end of flap.