The Influence Of Resveratrol On The Survival Of Rat Random Pattern Skin Flap

Random pattern skin flaps have been an important tool to repairing wounds, reconstructing organs and tissue transplantation in plastic surgery. Because the flap lacks the known artery to supply blood, the long-broad ratio of the flap has to be restricted to a certain extent to avoid the necrosis of distal end of the flap and which has restricted the clinical application of that flap. Many experts had made large of research work on the treatment and prevention of the necrosis of skin flap, and there are some theories of the mechanism of the necrosis of distal skin flap ,such as calcium overload, neutrophil infiltration, oxygen free radical damage, which have not been completely elucidated. However, lots of researches show that the ischemia reperfusion tissue injury is a key cause of the flap necrosis. The oxygen free radical (OFR), lipid peroxidation (LPO) and the activated neutrophils produced during the ischemia reperfusion process also plays an important role in the process of the necrosis of flaps. The Res could remove the oxygen free radicals, decrease the lipid peroxide and prevent the activation and accumulation of the neutrophils. While the reported study concerning of the application of the Res on the random pattern flap is rare, the object of this study is to investigating the effects of Res on the survival of the ischemic random pattern flaps in rats and discussing some possible mechanism which contribute to the survival of the flaps.There are two parts in this study. The object of partⅠis to observe the influence of Res on the random pattern flap, and the differentiation of different dose of Res; The object of partⅡis to observe the influences of two different ways of using Res on the flap, and the comparison of the two ways.Methods:PartⅠ: Fifty-two female Sprague-Dawley rats were used in the study. The rats were divided into four groups of thirteen rats each: control groups (A group),low-dose of Res groups(B group),middle-dose of Res groups(C group),high-dose of Res groups(D group). .In B,C,D group, 50mg/kg of Res,100mg/kg of Res,150mg/kg of Res was administrated into stomach respectively every day three days before operation. A caudally based dorsal random pattern skin flap, measuring 3cm×9cm was symmetrically raised. At the time of 24h after operation,5 rats from each group were sacrificed, and three full thickness tissue samples were taken from three point which are 2,5 and 7cm far from the pedicel respectively. The tissue sample were homogenized for Myeloperoxidase(MPO) and Malondialdehyde(MDA) examinations. Seven days after operation, the skin paddle survival of remaining 8 rats of each group was measured. The animals were then sacrificed and the tissue samples from proximal, middle, and distal portions were sectioned with haematoxylin-eosin staining for histological analysis.Results:1.Seven days postoperatively, the percentage of the flap's surviving area of B, C and D group is significantly higher than A group respectively(P<0.01);There are no significant difference between C group and D group(P>0.05); the percentage of the flap's surviving area of C and D group is significantly higher than B group(P<0.01); 2.At 24th hour postoperatively, MPO activity, MDA content of the flap tissue in each group in the distal portion is significantly higher than that of middle and proximal portions, and in the middle portion is significantly higher than that of the proximal portions; MPO level is significantly lower in B,C,D groups compared to A group respectively in the proimal, middle and distal portions (P<0.01);There are no significant difference between C group and D group in the three portions respectively (P>0.05);MPO level of each portion of B group is respectively significantly higher than C and D group(P<0.01); MDA level is significantly lower in B,C,D groups compared to A group respectively in the proximal, middle and distal portions (P<0.01);There are no significant difference between C group and D group in the three portions respectively (P>0.05);MDA level of each portion of B group is respectively significantly higher than C and D group(P<0.01);3.Edema and infiltration of neutrophils observed in tissue section in B,C,D group is slighter than that of A group.PartⅡ:Thirty-nine female Sprague-Dawley rats were used in the part. The rats were divided into three groups of thirteen rats each: control groups(A group), Res administration by gavage group(B group) and Res liniment treatment group(C group).Flap design of testing indexes are the same as the partⅠ.Results: 1.Seven days postoperatively, the percentage of the flap's surviving area of B and C group is significantly higher than A group respectively (P<0.05);There are no significant difference between B group and C group(P>0.05).2.At 24th hour postoperatively, MPO activity, MDA content of the flap tissue in each group in the distal portion is significantly higher than that of middle and proximal portions, and in the middle portion is significantly higher than that of the proximal portions; MPO level is significantly lower in B and C groups compared to A group respectively in the proximal, middle and distal portions (P<0.05);There are no significant difference between B group and C group in the three portions respectively (P>0.05); MDA level is significantly lower in B and C groups compared to A group respectively in the proximal, middle and distal portions (P<0.05);There are no significant difference between B group and C group in the three portions respectively (P>0.05);3.Edema and infiltration of neutrophils observed in tissue section in B and C group is slighter than that of A group.Conclusion: Res can increase the survival of random pattern skin flap through intragastric administration and liniment treatment, and the curative dose of intragastric administration of Res is 100mg/kg/d.