VAC 技术治疗兔耳缺血性创面的实验研究

目的:观察间歇和持续负压下缺血创面不同处理与愈合的关系。方法:实验前1天,用脱毛剂(Nair,美国)对兔耳背脱毛。动物用1%戊巴比妥钠耳缘静脉注射麻醉(30 mg/kg体重),固定于手术台。75%乙醇消毒双侧耳背皮肤。距耳根3-3.5cm处分离、结扎兔耳中央神经血管束。在耳背中部形成直径2.5cm全层皮肤缺损创面(保留软骨膜)1]。止血后置动物于特制木盒内。42只大白兔共84个创面,随机分为-50mmHg-75mmHg和-100mmHg 3大组,分别施以间歇负压(运行2分钟,停1分钟)和持续负压组。实验分别运用-50mmHg,-75mmHg,-100mmHg三个不同负压值进行连续、间歇治疗兔耳缺血性创面,观察伤后1,3,7,10,14,20d创面愈合情况,取伤后7d组织标本进行Western blot、HE染色,观察VEGF(vascular endothelial growth factor)的表达及创面上皮的再生和肉芽组织生长情况1]。以及各时间点细胞凋亡的检测。结果:-50mmHg(纱布+海绵)间歇负压引流技术治疗兔耳缺血性创面的愈合最快,-75mmHg治疗组次之,-100mmHg治疗组创面愈合最慢。在同一时间点上,-50mmHg治疗组与-75mmHg,-100mmHg治疗组和空白对照组之间相比,能够更快地促进创面VEGF的表达和肉芽组织的再生,毛细血管增多。封闭负压治疗能够降低创面组织细胞的凋亡的发生。结论:(1)封闭负压治疗能够促进缺血创面的肉芽组织再生及VEGF的表达,减少创面组织细胞的凋亡的发生;(2)-50mmHg间歇封闭负压治疗效果最好。

Experimental Study on the Ischemic Wound Treated by VAC in Rabbit Ear

Objective: To observe the relationship between the wound healing and continuous or intermittent negative pressure treatment.Methods: The ear of wach rat was molted with depilatory(Wair,carfer,NY).The animals were anesthetized by ear vein injection of 1% sodium pentobarbital(30 mg/kg bady weight) and fixed on the operating table.The bilateral ear skin was disinfected with 75% ethanol and a fullthickness skin wound,2.5cm in diameter,3-3.5cm away from the ear rout was created in each ear.The central neurovascular bundle of the ear was ligated(retain the perichondrium).After stop bleeding,the animal was placed in a specially made wooden box.There were 42 rabbits with 84 ischemic wounds were randomly divided into 3 major groups in which every group has-50mmHg,-75mmHg,-100mmHg negative pressure group,and each subjected to intermittent negative(2 minutes on,1 minute off) or continuous treatment.At 1,3,7,10,14,20d after wounding and immediate treatment,the wound healing was evaluated,and taking the 7th day tissue samples for western blotting,HE staining,VEGF expression,and histological examination for epithelial regeneration,granulation formation,and apoptosis detection.Results: The wounds treated by-50mmHg negative pressure healed fastest,the-75 mmHg group second,and the-100 mmHg group,slowest.At the same time point,in-50mmHg negative group,the VEGF expression,granulation tissue formation,and capillary members significantly lager than that in other 2 groups,also the cell apoptosis significantly reduced.Conclusion: VAC thrapy can promote ischemic wound healing in rabbit dorsal ear.The reason is that it can promote VEGF expression,increase capillary and granulation tissue,and reduce cell apoptosis.