腺病毒介导基因转染提高大鼠皮瓣成活力的实验研究

目的 探讨局部应用腺病毒介导人血管内皮细胞生长因子,对大鼠全厚随意型皮瓣、轴型皮瓣成活率的影响.方法 按照皮瓣类型将SD大鼠分为随意型皮瓣与轴型皮瓣两组,每组随机分为腺病毒治疗组(AdCMCV-VEGF组)、半乳糖苷酶组(AdCMV-Gal组)与生理盐水组3组(每组10只).分别于大鼠背侧正中设计蒂在尾侧的随意皮瓣(8cm×2cm),于腹部设计双侧腹壁下动脉为蒂的联合轴型皮瓣.在AdCMCV-VEGFA组,在设计皮瓣远端真皮下注射1012pfu的重组复制缺陷型腺病毒;AdCMV-Gal组,同法注入1012pfu的重组复制缺陷型腺病毒AdCMV-Gal;生理盐水组注入生理盐水1ml.注射后3天,皮瓣按原设计掀起并原位缝合,轴型皮瓣同时行右侧腹壁下动静脉结扎.分别与7天(随意型皮瓣)、14天(轴型皮瓣)后计算皮瓣成活率.结果 与AdCMCV-VEGF组和盐水组相比,AdCMV-VEGF组皮瓣成活率明显增高,免疫组化染色检测证明VEGF表达.组织学检测证明AdCMCV-VEGF组肉芽组织形成与血管增生明显增多.结论 腺病毒介导的局部应用VEGF cDNA可明显提高缺血皮瓣的成活.     

pcDNA3.1(+)载体携带血管内皮生长因子治疗大鼠缺血皮瓣

目的 观察注射真核表达载体pcDNA3.1(+)携带血管内皮生长因子(VEGF)基因后对大鼠缺血皮瓣存活的影响.方法 构建重组质粒pcDNA3.1(+)-VEGF,将SD大鼠随机分成3组,每组10只.pcDNA3.1(+)-VEGF组:于背部皮肤皮下多点注射pcDNA3.1(+)-VEGF 30 μg/100μl;VEGF组:多点注射VEGF蛋白100 ng/100μl;生理盐水(NS)组:注射生理盐水100μl,注射2d后在其背部形成7 cm×3 cm的全厚随意型皮瓣,48 h后按原设计掀起皮瓣并原位缝合.术后10 d测量皮瓣的成活面积,计算成活面积百分比,并行免疫组织化学检测.结果 皮瓣成活面积百分比:pcDNA3.1(+)-VEGF组为(79.1±3.5)％,VEGF组为(62.2±2.7)％,NS组为(59.9±3.1)％,pcDNA3.1(+)-VEGF组皮瓣成活面积明显高于其他两组(P＜0.05).结论 皮下注射pcDNA3.1(+ )-VEGF可促进新生血管的形成,比单纯注射VEGF蛋白更能提高皮瓣的成活率.     

电脉冲介导的血管内皮细胞生长因子基因治疗对大鼠随意型皮瓣成活的影响

目的探讨血管内皮细胞生长因子(vascularendothelialgrowthfactor,VEGF)质粒直接皮下注射,结合直流电脉冲刺激的基因治疗方案的血管生成效应及不同剂量质粒对皮瓣成活的影响。方法设计大鼠随意皮瓣模型,利用直流电脉冲将皮下注射的重组质粒PCMVMCSVEGFIRES2EGFP导入缺血皮瓣内。观察皮瓣成活的情况,利用苏木素伊红(HE)染色,观察VEGF基因的血管生成效应。结果皮下直接注射结合直流电脉冲成功地将重组质粒导入皮肤。基因转染后7d观察到明显的血管增生。基因治疗组皮瓣成活面积[80μg为(77.38±4.56)%,400μg为(82.57±5.21)%]显著大于对照组[(48.96±4.32)%]。但两基因治疗组皮瓣成活面积差异无统计学意义。结论VEGF质粒直接皮下注射结合直流电脉冲刺激能够高效转染大鼠皮肤,具有明显的血管生成效应,能够显著促进大鼠随意型皮瓣的成活。质粒的剂量对皮瓣成活的影响差异无统计学意义。     

重组腺病毒介导的血管内皮生长因子165基因增强大鼠横形腹直肌肌皮瓣活力的研究

目的探讨重组腺病毒介导的血管内皮生长因子165(adenovirusmediatedvascularendothelialgrowthfactor165,Ad-VEGF165)基因,增强大鼠横形腹直肌肌皮瓣(transverserectusabdominismusculocutaneousflap,TRAM)局部缺血区域活力的基因治疗。方法SD大鼠30只,制备30mm×80mm以下腹部血管作为血管蒂的右侧矩形TRAM皮瓣,随机平均分成5组,分别在大鼠TRAM皮瓣皮下、皮下+腹直肌及腹直肌局部注射Ad-VEGF165(1～3组:治疗组),同时在TRAM皮瓣皮下+腹直肌局部注射重组腺病毒载体介导的绿色荧光蛋白(adenovirusmediatedgreenfluorescentprotein,Ad-GFP,4组:重组腺病毒自身对照组)和DMEM培养液(5组:空白对照组),于注射后第7天手术,术后第7天检测各组大鼠TRAM皮瓣成活面积、CD34微血管密度(microvasculardensity,MVD)、VEGF免疫组织化学染色和原位杂交组织化学(insituhybridizationhistochemistry,ISHH)。结果11～3组TRAM皮瓣成活面积分别为14.19±2.77、15.18±2.18、8.30±1.28cm2,均较4、5组4.12±1.86、3.60±1.95cm2明显增加,且差异有统计学意义(P<0.05);21～3组TRAM皮瓣CD34MVD均高于4、5组,差异有统计学意义(P<0.05);31～3组VEGF免疫组织化学染色和ISHH呈阳性表达。结论重组腺病毒载体介导的VEGF165基因局部注射,能增加大鼠TRAM皮瓣局部缺血区域成活面积。     

转基因的骨髓间充质干细胞治疗大鼠缺血皮瓣

目的探讨转染血管内皮细胞生长因子(VEGF)基因的大鼠骨髓间充质干细胞(MSCs)同种异体移植促进缺血皮瓣的血管新生,从而提高皮瓣存活率的可能性。方法体外分离、培养、鉴定SD大鼠MSCs,PcDNA3.1(-)/VEGF165质粒转染MSCs,免疫荧光方法检测MSCs体外表达VEGF的情况,CM-DiI标记MSCs。SD大鼠随机分3组:A组[PcDNA3.1(-)/VEGF165质粒转染的MSCs移植]、B组(单纯MSCs移植)、C组(DMEM-F12培养基)。每只大鼠背侧皮下按组分别注射细胞悬液和培养基,注射后ELISA法连续检测大鼠血浆VEGF浓度,注射后第4天掀起1个蒂在尾侧的9 cm×2 cm的随意皮瓣。在术后第14天分别观察皮瓣的存活率、激光多普勒血液监测仪监测血流灌注、CD34免疫组织化学检测皮瓣毛细血管密度、荧光显微镜检测MSCs在皮瓣内的分布和存活状况。结果转染VEGF165基因的MSCs体外和体内检测均高表达VEGF165蛋白。A、B、C三组的皮瓣存活率分别为(83.1±2.6)%、(66.4±6.1)%、(51.5±7.5)%(P< 0.05);A、B、C三组的毛细血管密度(条/mm2)分别为:89.2±6.1、57.1±4.7、28.7±2.8(P< 0.05);血流灌注比值A组高于B、C两组,B组高于C组(P<0.05);转染VEGF165基因的MSCs移植SD大鼠皮瓣后,MSCs存活并参与血管新生。结论转染VEGF基因的大鼠MSCs体外培养后异体移植可促进缺血皮瓣的血管新生,提高存活率。     

bFGF对促进大鼠移植缺血皮瓣血管化的实验研究

目的 探讨碱性成纤维细胞生长因子(bFGF)对大鼠移植皮瓣成活作用的影响.方法 Wistar大鼠48只,按月龄随机分为A、B、C、D四组,每组12只.制作移植皮瓣模型.A、C组的大鼠多次多点每点注射bFGF 60 U(0.015 ml);B、D组给予等量生理盐水作为对照.分别于5 d、14 d观察皮瓣的存活率,分别取相同部位皮瓣组织块行病理组织学检查,并采用计算机图像分析系统和免疫组化方法计算血管密度和血管内皮生长因子(VEGF)阳性血管数.结果 大鼠缺血皮瓣血管密度及VEGF阳性表达的血管数A组[(分别为(134.21±4.86)个/mm~2,(14.63±2.25)条]多于B组[分别为(118.48±2.31)个/mm~2,(7.45±1.43)条],C组[分别为(128.67±4.58)个/mm~2,(11.39±1.61)条]多于D组[分别为(115.32±2.18)个/mm~2,(6.96±1.35)条],差异均有统计学意义(P<0.05);A组和C组比较,差异无统计学意义(P>0.05).结论 在不同月龄大鼠移植皮瓣内注射bFGF蛋白可促进皮瓣血管新生,改善移植皮瓣缺血状态,提高皮瓣成活率.     

早期反复短时缺血训练对皮瓣成活的影响及其机制研究

目的观察早期反复短时缺血训练对皮瓣成活面积、血管内皮生长因子(vascularendothelialgrowthfactor,VEGF)及微血管密度(microvesseldensity,MVD)的影响。方法取日本大耳白兔72只,随机选取64只为实验组,在其背部两侧对称位置建立蒂在上端的皮瓣区,皮瓣范围为4cm×3cm。随机选一侧为训练皮瓣组(A组),另侧为对照皮瓣组(B组),其余8只背部两侧相同部位标记后不作处理,为空白对照组(C组)。术后即对A组皮瓣蒂部进行反复短时缺血训练。分别于术后1~8d每天随机取实验组8只断蒂,检测A、B组各时间点皮瓣成活面积;并于各时间点检测A、B组皮瓣和C组相应部位皮肤组织内的VEGF相关系数和MVD值。对A组皮瓣成活面积VEGF相关系数和MVD值行相关分折。结果术后动物全部成活,无感染、死亡,活动情况无明显变化。A组3~8d皮瓣成活面积较B组高,差异有统计学意义(P<0.05)。A、B组各时间点VEGF表达及MVD值均较C组高;A组1~6dVEGF表达高于B组,差异有统计学意义(P<0.01);且A组各时间点MVD值高于B组,差异有统计学意义(P<0.05)。相关分折见A组皮瓣成活面积与MVD、MVD与VEGF成正相关,时间点对应关系为n与n-2;相关系数分别为0.850和0.801。结论早期反复短时缺血训练可提高皮瓣成活面积,利于早期断蒂,其机制可能为训练使VEGF表达增强,进而增加皮瓣微血管密度,加速皮瓣血供重建。     

脂质体介导血管内皮生长因子对不同时间断蒂大鼠随意型皮瓣的影响

目的 通过血管内皮生长因子基因对大鼠随意型皮瓣的转染,探讨基因治疗对不同时间断蒂的大鼠随意型皮瓣成活的影响.方法 以SD大鼠为实验模型制作背部随意型皮瓣,实验组注入脂质体包裹的PcDNAVEGF165(目的 基因组),对照组分别注入PcDNA(空白质粒组)和生理盐水(生理盐水组),于用药后1、3、5、7 d,每组每时相点分别随机选取10只断蒂,断蒂后7 d处死大鼠,观察下述指标:①皮瓣成活率.②皮瓣组织标本行常规HE染色检测平均微血管数目及内径.③行VEGF免疫组织化学染色检测VEGF表达情况.④取皮瓣组织标本在电镜下观察超微结构.结果 ①皮瓣成活率:1、3、5、7 d断蒂实验组皮瓣成活率分别为(45.45±12.24)%、(82.95±3.81)%、(85.00±3.38)%、(85.96±3.25)%.1 d断蒂实验组与对照组比较差异无统计学意义(P>0.05),3、5、7 d断蒂各实验组明显高于相应对照组(P<0.05),3、5、7 d断蒂各实验组则随着断蒂时间的延迟差异无统计学意义(P>0.05).②平均微血管数目及内径:各实验组与相应对照组比较差异有统计学意义(P<0.05).③各实验组VEGF染色深度明显高于对照组(P<0.05).④超微结构:实验组内有新生血管形成,内皮细胞内可见较多粗面内质网,线粒体等结构,组织内成纤维细胞增多,细胞合成代谢旺盛.结论 皮下注射脂质体介导VEGF基因可提高皮瓣成活率,促进早期断蒂,是一种简单,高效,经济,相对安全的基因治疗方法.     

VEGF明胶缓释微球对大鼠背部随意皮瓣存活的影响

目的研究局部注射血管内皮生长因子(VEGF)复合明胶微球对SD大鼠背部随意皮瓣存活的影响.方法采用改良的乳化冷凝法交联制备复合VEGF的明胶缓释微球,将其注射于大鼠背部随意皮瓣,24只SD大鼠随机分为复合VEGF微球组(A组)、VEGF治疗组(B组)和对照组(C组),术后7天分别进行皮瓣存活率、新生血管计数的检测.结果术后7天皮瓣的存活率分别为(68.54±2.79)%,(58.65±3.26)%,(45.43±2.71)%,治疗组存活率显著高于对照组(P＜0.05),且存活质量A组最好;皮瓣内新生血管计数分别为(31.16±4.38),(25.41±4.06),(18.68±5.44)具有显著差异性.结论VEGF缓释微球可以促进缺血皮瓣的血管新生,提升皮瓣存活率.     

重组人VEGF基因治疗大鼠缺血TRAM皮瓣的观察

目的研究重组人VEGF基因对大鼠缺血TRAM皮瓣成活的影响,探讨基因治疗缺血皮瓣的可能性及疗效.方法动物实验分4组,实验组每只皮下注射PcDNA3.1VEGF 500μg;阳性对照组每只注射VEGF 100ng;空白对照组每只注射生理盐水1 ml;阴性对照组每只注射PcDNA3.1 500μg.用ELLSA法及免疫组化法测定VEGF基因表达水平,测定皮瓣成活面积及皮下组织中微血管密度,观察该基因对皮瓣成活的影响.结果实验组皮瓣成活面积及切片微血管密度显著高于阴性对照组及空白对照组(P＜0.05),与阳性对照组差异无显著性意义(P＞0.05).免疫组化显示实验组中有大量棕褐色抗原抗体复合物沉积在小血管内皮细胞胞浆内.结论直接皮下注射PcDNA3.1VEGF,可在注射部位表达具生物活性的VEGF,促进皮下微血管形成,提高缺血TRAM皮瓣的成活面积.     

Effect of adenovirus-mediated gene transfection of vascular endothelial growth factor on survival of random flaps in rats

Objective: To evaluate the effect of local application of vascular endothelial growth factor ( VEGF ) via adenovirus-mediated gene transfer on survival of full thickness flaps selected randomly in rats.Methods: Thirty Sprague-Dawley rats weighing 480-520 g were used in this study. A dorsal flap (8 cm × 2 cm) in full thickness with the pedicle located at the level of the iliac crest was designed. Then the rats received 1 012 pfu replication-deficient recombinant adenovirus carrying VEGF ( AdCMV-VEGF group, n = 10 ), 1012 pfu recombinant β-galactosidase adenovirus ( AdCMV-Gal group, n = 10) and 1 ml saline (saline group, n = 10), respectively, in the distal two thirds of the proposed flap by means of subdermal injection at 8 different locations. Three days after treatment, the flaps were elevated as originally designed and sutured back in situ. The survival rate of the flaps was evaluated on day 7 after operation.Results: The survival rate of the flaps in the AdCMV-VEGF group increased significantly as     

血管内皮生长因子基因治疗联合外科延迟法改善大鼠腹壁超范围轴型皮瓣成活的研究

目的探讨皮下注射血管内皮生长因子（vascular endothelial growth factor,VEGF）基因、外科延迟两种方法及其联合应用对大鼠腹壁超范围轴型皮瓣成活的影响。方法取雄性Wistar大鼠48只,体重400～450g,制作大鼠以腹壁浅动脉为血管蒂的8cm×8cm超范围轴型皮瓣模型。随机分为六组,每组8只,分别为空白对照组（A组）、术时基因治疗组（B组）、术前基因治疗组（C组）、单纯延迟组（D组）、延迟同时基因治疗组（E组）和延迟后基因治疗组（F组）。术后7d,计算各组的皮瓣成活率;取皮瓣组织标本行HE染色,检测平均微血管密度及内径;取皮瓣组织标本行VEGF免疫组织化学染色检测VEGF165的表达。结果各实验组皮瓣成活率均显著高于A组（P〈0.05）;实验组中,E组皮瓣成活率显著高于其他各组（P〈0.05）,余各实验组间差异无统计学意义（P〉0.05）。微血管密度：B、C、E、F组显著高于A、D组,差异有统计学意义（P〈0.05）;B、C、E、F组间以及A、D组间比较差异无统计学意义（P〉0.05）。微血管内径：D组显著大于E、F组,差异有统计学意义（P〈0.05）;而D组和E、F组均显著大于A、B、C组,差异有统计学意义（P〈0.05）。免疫组织化学染色示A组及D组有少量VEGF165沉积,染色深度明显浅于其他各组。B、C组和E、F组可见毛细血管内皮细胞胞浆内有棕褐色VEGF165抗原抗体复合物的沉积,染色较深,部分沉积物呈带状围绕血管腔。各组实验动物角膜层均未见新生血管。结论皮下注射pcDNA4-VEGF165和外科延迟均能有效改善大鼠皮瓣的成活,但二者作用机制不同,而延迟的同时皮下注射VEGF基因能进一步提高大鼠皮瓣成活率。     

Endothelial cell growth factor enhances musculocutaneous flap survival through the process of neovascularization

The effect of an angiogenic growth factor-endothelial cell growth factor (ECGF)-was tested in the rat transverse rectus abdominis musculocutaneous (TRAM) flap model based on a single inferior vascular pedicle. The animals were divided into three groups (N = 8 per group) after flap elevation. In group A (control), each animal received both local and local intra-arterial injections of 1 ml saline. In group B (local), each received a 2-mg ECGF local injection and 1-ml saline local intra-arterial injection. In group C (local intra-arterial), each received a 1-ml saline local injection and a 2-mg ECGF local intra-arterial injection. All animals were evaluated on postoperative day 7. There was a significant increase in the percentage of the skin paddle survival area of the TRAM flap in both ECGF-treated groups when compared with the control group (group B vs. group A, p < 0.001; group C vs. group A, p < 0.001). This correlated with a significant increase in vascularity in both ECGF-treated groups compared with the control group (group B vs. group A, p = 0.007; group C vs. group A, p = 0.021). The results between groups B and C were not significant. ECGF, when administered via either local or local intra-arterial route, enhances musculocutaneous flap survival through the process of neovascularization.     

转染血管内皮生长因子基因的小鼠NIH3T3细胞移植促进皮瓣早期血运重建的研究

目的探讨转染血管内皮生长因子（VEGF）基因的小鼠NIH3T3细胞移植对缺血皮瓣的血管新生和皮瓣存活率的影响。方法体外PcDNA3．1（-）／VEGF165质粒转染小鼠NIH3T3细胞,免疫组化方法检测小鼠NIH3T3细胞体外表达VEGF的情况,CM-DiI标记小鼠NIH3T3细胞。将小鼠随机分为3组：A组[PcDNA3．1（-）／VEGF165质粒转染的NIH3T3细胞移植]、B组（单纯NIH3T3细胞移植）、C组（单纯DMEM培养基注射）。每只小鼠背侧皮下按组分别注射细胞悬液和培养基,注射后酶联免疫吸附（ELISA）法连续检测大鼠血浆VEGF浓度,注射后第4天掀起一个蒂在尾侧的4．0cm×1．5cm的随意皮瓣。术后第7天分别观察皮瓣的存活率、血流灌注、皮瓣毛细血管密度、NIH3T3细胞在皮瓣内的分布和存活情况。结果转染VEGF165基因的小鼠NIH3T3细胞体外和体内检测均高表达VEGF165蛋白。A组的皮瓣存活率、毛细血管密度、血流灌注比值均显著高于另外两组（P〈0．05）。结论转染VEGF基因的小鼠NIH3T3细胞皮下移植可促进缺血皮瓣的血管新生,提高存活率。     

Enhancement of ischemic flap survival by prefabrication with transfer of exogenous PDGF gene

Treatment of skin flaps by means of gene therapy has been introduced recently as a novel approach to enhance viability of ischemic skin flaps. Transfer of the platelet-derived growth factor (PDGF) to enhance survival of the ischemic skin flap has not been explored. In this study, the authors investigated the effect of the transfer of the PDGF cDNA on survival and vascularity of the ischemic random flap in a rat model, and compared the effects of PDGF gene therapy to those of vascular endothelial growth factor (VEGF) gene therapy. A total of 45 adult Sprague-Dawley rats were randomly divided into four groups. The PDGF gene therapy group (n=10) received the plasmid containing the PDGF cDNA with liposome injected to the dermis of the flap. A saline control group (n=10) received physiologic saline only, and the vector control group (n=10) received liposome plus vector without the PDGF gene segment. In the fourth group (n=15), the VEGF gene was transferred to the flap. Seven days later, a dorsal random flap including the injection area was raised. One rat each from the saline and vector control groups died during the study period and were excluded. The viability of the flap and vascularity within the flaps were assessed 7 days after flap elevation. The PDGF plasmid-treated flaps had significantly greater survival area (60.8+/-7.8 percent) compared with the flaps treated with saline (52.3+/-5.0 percent) and those treated with liposome and vector (50.7+/-5.9 percent). PDGF gene therapy had effects on survival of the flap similar to VEGF gene therapy (57.6+/-5.2 percent, after transfer of VEGF cDNA). Neovascularization with the flap tissues was confirmed by immunohistochemical staining of von Willebrand factor, a marker specific for angiogenesis. The number of newly-formed blood vessels in the transgenic flaps was significantly greater than that of the vessels in the flaps receiving the saline. The findings of this study indicate that transfer of the PDGF cDNA effectively enhances neovascularization of the ischemic skin flap and increases the viability of the flap, and transfer of the PDGF gene is as efficient as transfer of the VEGF gene in improving viability of the skin flap. This study suggests that PDGF gene therapy may be a novel strategy for the treatment of ischemic skin flaps.     

Improvement of skin paddle survival by application of vascular endothelial growth factor in a rat TRAM flap model

The effect of vascular endothelial growth factor (VEGF) on skin flap survival and its ability to induce a pharmacological delay by promoting angiogenesis in a flap was studied in a rat transverse rectus abdominis musculocutaneous flap, using a 3 x 8-cm skin paddle with the inferior epigastric vessels as its main vascular supply. Forty-three Sprague-Dawley rats were divided into four groups. In group 1, VEGF was injected into the femoral vein after the flap was elevated. In group 2, VEGF was injected intra-arterially into the flap through the superior epigastric artery after the flap was elevated. In group 3, VEGF was injected into the subcutaneous fascial layer in the area where the flap would be dissected, and the flap was then raised 7 days after injection. In group 4, the flap was dissected and replaced, using saline injection as the control. On postoperative day 5, the survival area of each skin paddle was measured and the flap was harvested for histological analysis. The results showed that the mean survival area +/- standard deviation for the skin paddle was 6.82 +/- 4.89 cm2 (28.4 +/- 20.4% of the whole skin paddle) in the control group, and 4.2 +/- 3.0 cm2 (17.5 +/- 12.5%) and 6.02 +/- 5.97 cm2 (25.1 +/- 24.9%) in the groups with VEGF systemic and intra-arterial administration respectively. The skin survival area in the group with preoperative subcutaneous administration of VEGF was 17.85 +/- 2.88 cm2 (74.4 +/- 12%), which was significantly higher than the other three groups (p < 0.01). Histological semiquantitative analysis showed increased neovascularization in the flap treated with VEGF preoperatively. The data demonstrate that preoperative treatment with VEGF can induce angiogenesis and enhance skin paddle survival in a musculocutaneous flap.     

The effects of VEGF on survival of a random flap in the rat: examination of various routes of administration.

The purpose of the present study was to determine the effects of vascular endothelial growth factor (VEGF) on survival of a full thickness random pattern, McFarlane musculocutaneous flap in the rat. In addition, this study examined a number of different methods of VEGF delivery in an attempt to determine the most effective route of administration. A 2 x 8 cm full thickness dorsal flap with the pedicle remaining attached at the anterior end was elevated in 72 male Sprague-Dawley rats. The rats were randomised into six groups and immediately received the following treatment: Group I (n = 12): systemic VEGF injection into the femoral vein (50 microg/ml); Group II (n = 10): multiple systemic VEGF injections at 0, 24 and 48 h post flap elevation (50 microg/ml); Group III (n = 12): subdermal VEGF injection into the flap (1 microg/ml); Group IV (n = 12): subfascial VEGF injections into the recipient bed (1 microg/ml); Group V (n = 10): topical VEGF onto the recipient bed (1 microg/ml); Group VI (n = 16): control group with no treatment. Following 5 days recovery, the area of flap survival was measured. Mean flap survival ranged from 91% in Group II to 78% in Group V, and was significantly greater in all experimental groups (P< 0.001 for Groups I-IV and P< 0.05 for Group V) as compared to the control group (mean survival of 66%). The only significant difference between the experimental groups was between the mean survival in Group II and Group V (P< 0. 05). Histological analysis demonstrated a qualitatively greater amount of granulation tissue and neovascularisation in the experimental groups. These results support the notion that VEGF rescues tissue at risk of hypoxic damage by inducing angiogenesis, and the use of growth factors such as VEGF holds promise as a method of increasing skin viability.     

Expansion of surviving skin paddle of neurocutaneous island flaps in rats by VEGF

The purpose of this study was to investigate whether vascular endothelial growth factor (VEGF) can enlarge the skin paddles of neurocutaneous flaps in rats. Wistar albino rats were used in four groups: Group 1, (n = 10): neurocutaneous island flap; Group 2, (n = 10): neurocutaneous island flap, surgical delay; Group 3, (n = 10): neurocutaneous island flap, VEGF; Group 4, (n = 10): graft. A 3 x 3-cm, neurocutaneous island flap was elevated on the anterolateral skin of the thigh of the rats. The surviving flap areas were 29.7 +/- 1.43 percent in Group 1, 41.3 +/- 3.24 percent in Group 2, 94.2 +/- 1.46 percent in Group 3. There were no surviving areas in Group 4. The vascular networks of Group 3 animals were more intensive and diffused on microangiography and the histopathologic findings were better in this group. The surviving flap areas in Group 3 animals were enlarged approximately three times over the original size.     

Angiogenic effects of injected VEGF165 and sVEGFR-1 (sFLT-1) in a rat flap model

BACKGROUND: Injections of single-dose vascular endothelial growth factor (VEGF)(165) have been advocated as a therapeutic tool for angiogenesis in ischemic flaps. We challenged this thesis by employing both VEGF(165) and vascular endothelial growth factor receptor-1 (VEGFR-1) (for competitive inhibition of VEGF signal transduction) in different experimental settings of an ischemic rat flap model. MATERIAL AND METHODS: 80 isogenic rats were divided in two groups of 40 animals (groups 1A-1D and 2A-2D). The ischemic target was a 7 x 7-cm epigastric island flap, based on the right inferior epigastric pedicle. Group 1 received flap treatment 1 week prior to flap elevation by test substance injection into its flap panniculus carnosus: 1 ml NaCl 0.9% (1A), 1 ml Dulbecco's modified Eagle's medium (1B), 1.0 microg VEGF(165) (1C), and 10 microg sFLT-1 with 1.0 microg VEGF(165) (1D). sFLT-1 is a soluble receptor for VEGF and is able to prevent VEGF signaling through the cell surface receptor. Group 2 had the same flap treatment at the day of flap elevation. RESULTS: In group 1C we found the most vital flap tissue, without reaching significance. Compared with group 1D, however, significantly more flap tissue maintained vital. In groups 2A-2D, no significant results were found with respect to flap survival. CONCLUSIONS: Local application of single-dose VEGF(165) 1 week prior to ischemia dose not have significant clinical angiogenic effects. In this experimental setting, VEGF(165)-induced angiogenic effects can be significantly inhibited by adding sFLT1 in vivo. A single-dose of VEGF(165) under ischemic conditions causes no significantly better flap survival in this model.