OBJECTIVETo investigate the effect of VEGF (vascular endothelial growth factor) gene therapy and skin flap delay on the survival of rat's abdominal axial skin flap.

METHODSIn 48 Wistar rats, the model of a abdominal axial skin flap supplied by right superficial epigastric vessel was created. The rats were divided into six groups. The group was treated with subcutaneous injection of pcDNA4-VEGF165, skin flap delay or VEGF injection combined with skin flap delay. 7 days later, the survival rate of the skin flap was measured; specimens were harvested from the skin flap for histological investigation of the microvessels and for immunohistochemical staining to observe the expression of VEGF.

RESULTSEvery treated group was significantly higher than blank group in the average survival rate of the skin flap and group V (gene injection when delayed) has the highest one. The average number of the microvessels in group II, III, V, VI was significantly higher than group IV and blank group. Group IV > group V, VI > group II, III > blank group in lumen diameter of the microvessels. Immunohistochemical staining documented more deposition of VEGF DNA in group II, III, V, VI than group IV and blank group.

CONCLUSIONSBoth administration of pcDNA4-VEGF165 and skin flap delay can improve the survival of rat's abdominal axial skin flap, but the mechanisms of the effect were different. The combination of the two ways has stronger effect.