The Effects Of BFGF-PLGA Sustained Release Microspheres Survival Rate In The Back Expanded Skin Flap

Objective：To prepare poly lactide-co-glycolide sustained release (PLGA) sustained releasemicrospheres containing basic fibroblast growth factor(bFGF-PLGA-MS) andobserve their effects of survival rate in the back expanded skin flap of rabbit.Methods:24healthy, weight of1.6~2.1kg，female or male rabbit, after weight, wererandomly divided into3groups (n=8): NS+empty microspheres group, bFGF+empty microsphere group, bFGF-PLGA-MS group.24hours before operative,prepared and disinfected skin of back in rabbit, then implanted expanders(I period),and injected6ml of saline into the dilators. All the rats were fed adaptively for1week, repeat injected6ml of saline into the dilators every four days, a total of5timesand30ml of saline. After finished injection of three days, began to design flap afterexpansion (Ⅱ period).The size of rectangle flap was2cm by8cm,using anterioriliac crest as the axis. Then chosen15points of injection according to the flap area,the points were symmetrical and2cm apart, every point injected0.1ml solution.Group of bFGF-PLGA-MS injected containing bFGF-PLGA sustained releasemicrospheres solution; bFGF+empty microsphere group injected empty microspheresinjection and bFGF solution; empty microsphere group injected the same dosed emptymicrosphere and saline instead.12days latter, calculated skin flap survival area ofrabbit, then were sacrificed. After fixed paraffin embedded and hemateineosin staining,observed the pathological changes of the skin flap. Using immunohistochemicalmethod to detect CD34+expression, combined to the method of oxide gelatinspecimens perfused observation of microvascular density of skin flap. Results:1.12days postoperatively,the bFGF-PLGA-MS group, bFGF+empty microspheregroup, NS+empty microsphere group, the survival rate of skin flap area were about84.94±5.14%,62.72±7.12%and59.87±6.74%. The bFGF-PLGA-MS group washigher than that of bFGF+empty microsphere group, NS+empty microsphere group (P<0.05). The bFGF+empty microsphere group compared with NS+empty microspheregroup no significant difference (P>0.05).2. BFGF group-PLGA slow-release microspheres flap HE staining: distal endfull-thickness expansion flap necrosis, accompanied by obvious inflammationreaction, the nucleus concentration and burst; Cell contraction, smaller. And part thereis a certain degree of edema, skin flap survival, the thinning of the skin, with largearea of granulation hyperplasia, and formed a large number of new capillaries. BFGF+hollow microsphere suspension group and blank control group, the necrosis of skinflap is the same, but the survival of skin flap in no obvious hyperplasia of granulationtissue, new blood vessel growth is not obvious. BFGF group-PLGA slow-releasemicrospheres hyperplasia of granulation tissue and blood capillary hyperplasia withbFGF+hollow microsphere suspension group compared with blank control group,difference has statistical significance (P <0.05), but the bFGF+hollow microspheresuspension group compared with blank control group, there was no obvious statisticalsignificance difference (P>0.05).3. With bFGF+hollow microsphere suspension group compared with blankcontrol group, bFGF, PLGA CD34+expression of slow-release microspheres groupincreased significantly, difference have statistical significance (P <0.05). While its inbFGF+hollow microsphere suspension group and blank control group expression ofdifference is not obvious and has no obvious statistical significance (P>0.05).4. BFGF, PLGA slow-release microspheres, bFGF+hollow microspheresuspension group and blank control group on average three sets of flap vascularnumber respectively (37.38+5.90),(25.75+5.31),(24.13+4.76)/cm2, bFGF, PLGA slow-release microspheres group there are a large number of microvascular generation,group, blank control group and blank microspheres average blood vessel numberincreased obviously, and microvascular anastomosis with significantly more than theblank microspheres group experimental group and control group, difference hasstatistical significance (P <0.05). BFGF+hollow microsphere suspension group andblank control group to increase the number of blood vessels is not obvious, andconsistent with the less, the differences between the two groups has no statisticalsignificance (P>0.05).Conclusion:Subcutaneous injection of basic fibroblast growth factor-polylactide-co-glycolide sustained release microspheres can promote microvascularhyperplasia of the flap in back of rabbit, improved the long expansion flap survivalarea.