The effects of melatonin and N-acetylcysteine on McFarlane flap model in rats

Introduction and objectives: Flaps are widely used by plastic and reconstructive surgeons to cover open wounds. However the viability problem of the distal flap margins still remains a challenge. To overcome this problem many pharmaceutical agents such as peripheral vasodilators, antithrombotic agents, antioxidants and delay procedure are used in the literature. The proved positive effect of antioxidants to flap viability by eradicating free radicals is known.The aim of this experimental study is to show and compare the effects of melatonin and N- acetylcysteine on flap survival and also to examine the different impact when used together.Material and method: Forty Wistar Albino rats which weighs between 200-250 gr were used. Four groups of ten rats were formed. McFarlane flap model of 9x3 cm was prepared. To the rats in the first group (n=10), after the elevation of flaps intraperitoneal saline was administered for one week. To the second group (n=10) intraperitoneal melatonin (10mg/kg), to the third group (n=10) intraperitoneal N-acetylcysteine (40mg/kg) and to the fourth group intraperitoneal melatonin (10mg/kg) and n-acetylcysteine (40mg/kg) was administered everyday for one week. At the end of the week the experiment was terminated and pictures were taken for topographic studies, transillumination study was done to see the vascularization of flaps and biopsies were taken for the histopathologic studies.Findings: The necrosis areas of the flaps in the control group was %41,5±10,1, %22,2±12,5 in the second, %22,3±7,8 in the third and %22,2±10,0 in the last group. When the flap necrosis rate of the control group were compared with the rest of the groups, the result was significant. (p=0,002) In the histopathologic examination the necrosis rates and localization, edema, inflamation and vascular proliferation findings were studied. The necrosis findings in the control group was significantly higher. (p=0,001) The vascular proliferation findings in the control group was significantly lower. (p=0,035) Also, the vascular proliferation findings in the second group was significantly higher when compared to other groups. (p=0,029) The edema and inflamation parameters were higher in the control group but it was insignificant.(p>0,05)Result: Melatonin and N-acetylcysteine has positive effects on flap survival but there is no significant difference between these two agents. Also when they are combined, there were no significant increase of positive effects on flap survival. Melatonin and N-acetylcysteine, which are important antioxidants, can be used clinically to increase flap viability and to prevent distal necrosis.Key Words: antioxidants, viability of flap, melatonin, N-acetylcysteine, McFarlane falp