The Effects of Time Dependent Lipo-PGE1 Administration on Survival of a TRAM Flap in the Rat

ABSTRACT

The purpose of the present study was to examine a number of various times of Lipo-PGE1 administration in an attempt to determine the most effective time. In addition, this study examined the possible role of vascular endothelial growth factor(VEGF) on Lipo-PGE1 stimulation of a TRAM flap in the rat. Forty Sprague-Dawley rats were divided into 4 groups and a left inferior epigastric vessel pedicled TRAM flap, sized 5.0x3.5cm was created on the upper abdomen of each rat. Experimental groups included group 1(control) the flap was dissected and replaced, group 2(pharmacologic delay) Lipo-PGE1(0.5microgram) was given intraperitoneally for 5 days before elevation of flap daily, group 3(flap enhancement) Lipo- PGE1(0.5microgram) was given intraperitoneally for 5 days after flap elevation daily, group 4(pharmacologic delay and flap enhancement) Lipo-PGE1(0.5microgram) was given intraperitoneally for 5 days before elevation of flap then for 5 days after elevation of flap daily. On postoperative 5th day, we evaluated and compared the results of flap survival area, the number of blood vessel, and the VEGF expression using the western blot method. The results were as following First, the mean percentage of the flap survival area of group II(63.9+/-12.6%), III(54.9+/-20.5%), IV(68.1+/- 18.2%) were higher than that of group I(28.7+/-15.2%) significantly(p<0.05). Second, the number of blood vessels were of group II(3.8+/-1.4), III(3.5+/-1.8), IV(4.0+/-1.5) were higher than that of group I(1.0+/-0.6) significantly(p<0.01). Third, the western blot method demonstrated a qualitatively greater amount of VEGF expression in the experimental groups. These results suggest that Lipo-PGE1 increased VEGF production and that Lipo-PGE1 may thereby enhance flap survival through VEGF production regardless of the time of Lipo-PGE1 administration.