The effect of epigallocatechin gallate on the survival of random pattern skin flap

Abstract

Surgical skin flaps are often used in plastic and reconstructive surgery to repair defects resulting from trauma, congenital defects, tumor excision, or other causes. Partial or complete skin flap necrosis is a common problem encountered postoperatively. Epigallocatechin gallate (EGCG), the major polyphenol of green tea has been investigated as a vasodilator and antioxidant. The author’s hypothesis is that EGCG could improve viability of random pattern skin flaps through its vasodilatory effect, vasoprotective effect and neovascularization effect. The rat dorsal skin flap model was applied. Forty rats were randomly divided into four groups, with 10 rats in each group. Group A is the experimental group for local injection of EGCG to the flap. Group B is the experimental group for topical application. Group C is the control group for local injection. Group D is the control group for topical application. At 1, 5, and 10 days after the operation, the surviving area of the flap, regional blood flow, capillary density and VEGF expression were evaluated. We could observe increment of survival area in group A and B compared to group C and D (ANOVA, p < 0.05). However, no difference was observed between the two experimental groups. Doppler measurement showed greater blood flow in groups A and B compared to groups C and D in distal, middle and proximal portions of the flap. (ANOVA, p < 0.05) Between groups A and B, group B showed greater blood flow than group A only in the proximal portion. Quantitative analyses revealed that the capillary density and VEGF expression in groups A and B were significantly higher than those of groups C and D (ANOVA, p < 0.05). To summarize, the EGCG treatment could enhance neovascularization and enhance regional blood flow, and as a result, improve the skin flap survival. The topical application of EGCG seems to be more effective in increasing blood flow, however, the overall survival of the flaps showed no difference between local injection and topical application