RESUMEN
<p><b>OBJECTIVE</b>To investigate the effect of VEGF gene on the random flap survival after pedicle division at different time in rats.</p><p><b>METHODS</b>The random-pattern flaps were formed on the back of the 120 SD rats. PcDNAVEGF165 (gene) wrapped with liposome was injected into the flaps in experimental group (n = 40). The flaps in the two control groups were injected with PcDNA (n = 40) or saline (n = 40). 1, 3, 5, 7 days after injection, 10 rats in each group were randomly selected to performed pedicle division. 7 days after pedicle division, the rats were killed to measure the flap survival rate. The microvessels was studied by histologic examination. The expression of VEGF was assessed by immunohistochemical staining. The flaps were also examined under the electron ultrastructure microscopy.</p><p><b>RESULTS</b>1) Flap survival rate after pedicle division in experimental group at 1 day, 3 days, 5 days, 7 days after injection, were (45.45 +/- 12.24)%, (82.95 +/- 3.81)%, (85.00 +/- 3.38)%, (85.96 +/- 3.25)%, respectively. The flap survival rates were significant different between experimental group and the control groups at 3, 5, 7 days after injection (P < 0.05), but not at 1 days after injection (P > 0.05). 2) The average microvascular diameter and number in experimental group were significantly higher than those in control groups (P < 0.05). 3) The expression of VEGF in experimental group was significantly higher than that in the two control groups (P < 0.05). 4) Ultrastructure study showed more angiogenesis in experimental group.</p><p><b>CONCLUSIONS</b>Subcutaneous injection of liposome-mediated VEGF gene can increase the survival rate of flap with early pedicle division. It is a simple, efficient, economic, and the relatively safe gene therapy.</p>