Abstract:

Abstract:Objective To study  the effect of vascular endothelial growth factor (VEGF) on the viability of skin flap treated with radiotherapy at different time after operation and clarify its enhancing effect on angiogenesis.Methods Fifty Wistar rat were randomly divided into 3,5,7,9 d groups and control group.A 3 cm×4 cm full thickness dorsal flap with the pedicle remaining attached at the posterior end in rats and were treated with 60Co radiotherapy at the 2nd,4th,and 6th day postoperatively.The total quantity was 12 Gy.In the experiment groups every rat was given VEGF 120 ng on the 3rd,5th,7th and 9th day.The rats in control group were given the same quality normal saline and radiotherapy.Pathological observation,fluorescence staining and  sesuccinic dehyrogenase(SDH) assay were used to measure the blood vessel density,blood vessel diameter, Microcirculation and cell vitality of skin flap.Results In 5 d and  7 d VEGF group,the number of  average blood vessels and cells of the skin falp was increased  compared with control group（P<0.05）.In  9 d group,there was a significant increase of fiber cell layer and the thickness of the skin was increased.Fluorescence staining and SDH assay showed the flap active was highest in  the 7th day group.Conclusion The density and diameter of blood vessel are higher in the 7th day group than other groups.So the time of giving VEGF should be postponed properly.

Key words: vascular endothelial growth factor；radiotherapy；sink flap；rats,wistar