The Peripheral Revascularization Establishment Research Of BFGF, Ischemic Preconditioning On The Subcutaneous Vascular Net Free Skin

Objective:To investigate the impact of bFGF and ischemic preconditioning used in subcutaneous vascular net free skin in SD rats,such as the process of vascular cell increment and the area of maturity. Skin transplant is the main treatment of Hand Surgery, The basis of successful skin transplant is the establishment of blood supply between the skin and the skin grafting areas, blood vessel formation (angiogenesis in the proliferation and the formation process) is the foundation and key factors of this blood supply .Ischemic preconditioning and bFGF can accelerate the establishment of blood supply between skin and the skin grafting area and increase the survival rate of skin grafting.After the subcutaneous vascular net free skin grafting,the skin is too thick, moreover ,the establishment of blood supply needs a longer time, more difficult, and often appears local cortical necrosis, or dermal layer, there were a lot of piebald when the blisters were scattered.Ischemic preconditioning and bFGF are positive to these problems. bFGF is one of the most effective angiogenesis factor , which can accelerate the growth of endothelial cells and vascular smooth muscle cell , promote the formation of new capillaries strongly, increase the number of capillaries in the granulation tissue, thereby improve wound microcirculation, provide the necessary oxygen and rich inutrients for the organization. Ischemic preconditioning can induce the protective effect of skin. This effection will be immediate, moreover,which will be maintained for 24 hours, strengthen the ischemic tolerance capability for the cells, thereby which can trigger the protective effect. This experiment research the survival area and the establishment of blood supply in the margin of subcutaneous vascular net free skin when the basal blood supply has been failed, provide experimental evidence and clinical basis for clinical operation.Methods: 40 healthy SD rats are randomly divided into four groups.A:control group;B: Ischemic preconditioning ;C: Ischemic preconditioning and NS;D: Ischemic preconditioning and bFGF.A: Conventional skin preparations, disinfection,the length and width ratio is 1:1, spacing is 3 cm , the skin is set aside 1×1 cm2, 2×2 cm2, 3×3 cm2 in the dorsal zone with methylene blue.The formation process of the subcutaneous vascular net free skin is as follows: cut skin and subcutaneous tissue, the skin will be set off on the deep fascia, Hemostasis thoroughly and repair the majority of subcutaneous net free skin, retain subcutaneous fat about 1.5 to 3 mm, the skin and the grafting area is filled by the Skin Flake silica in order to block the blood supply of basement membrane ,the skin is reversed and sutured directly.B:the design is same to group A but cut only the edge of skin , after 72 hours ,free bottom skin basement , the skin and the grafting area is filled by the Skin Flake silica in order to block the blood supply of basement membrane, the skin is reversed and sutured directly C: the design is same to group A,cut only the edge of skin , after 72 hours, the skin and the grafting area is filled by the Skin Flake silica in order to block the blood supply of basement membrane,meanwhile the skin is soaked by 0.9% NS of 15 ml,10 min later , the skin is reversed and sutured directly D: the design is same to group A,cut only the edge of skin , after 72 hours, the skin and the grafting area is filled by the Skin Flake silica in order to block the blood supply of basement membrane,meanwhile the skin is soaked by bFGF36000 AU/15mL , 10 min later , reverse the skin films and suture it directly。We investigate the outcomes after 7 days.Measures: 1, observe the color, texture, flexibility and the situation of bleeding edge . 2, survival skin area: after one week, according the digital camera recording, measuring the longest diameter and the most width in the survival skin area, calculate the percentage of survival area. 3,histological observation:get pathological section in the margin of the subcutaneous vascular net free skin, HE staining, select five high-power microscope vision in the same width of the area randomly, measure the number of freshmen capillaries.Results: General observation :40 rats all survived after the whole feeding, the standards for judging skin necrosis is texture stiffen, lose flexibility and the color change into black. When the cutting scope is 1cm2, there is no difference in the four groups; When the cutting scope are 4cm2 and 9cm2,in the central part of the subcutaneous vascular net free skin,the skin lose flexibility and the color change into black.while in the margin of the skin,the color is good and the texture is flexible.there are significance of survival area and average width.(P<0.05).Q test show that there is no difference between groupB and C,the others are different. The survival area and average width of groupDis larger than groupA,Band group C. the survival area and average width of groupB,Cis larger than groupA. Histological observation: (1) the histological features of skin necrosis are similar in the four groups,they perform acute inflammation, neutrophil and mononuclear cell infiltration, muscle fibers necrosis.(2) In group A ,most of the cuticular layer is damaged.Each layer is destroyed and cound not be identificated clearly.There are a large number of neutrophils and monocytes.We can see rare of neogenetic micrangium . In Group B and C,We could find lots of micrangiums in the adipose layer . There are some big micrangiums in the dermis layer. Their lumenses are big and maintain integrity. In Group D,a small number of neutrophils and monocytes infiltrated in the skin.We could find plenty of micrangiums in the dermis layer and adipose layer.Most of them have big lumenses.The density of micrangium was larger than group B and C. When the cutting scope is 1cm2, The results of Capillary number is same to groupA,Band group C ; When the cutting scope is 4cm2 and 9cm2, there are significance of survival area and average width.(P<0.05), Q test show that there is no difference between groupB and C,the others are different.The results of Capillary number of groupD is larger than groupA,B and group C ; The results of Capillary number of groupB,C is larger than groupA.conclusion: (1)bFGF and ischemic preconditioning can directly accelerate proliferate and differentiation of fibroblasts, blood vessal endothelial cells,smooth muscle cells in granulation tissue,stimulate the formation of granulation tissue, promote blood capillary proliferatio,increase the number of blood vessal in granulation tissue, provide a better nutritional environment for the growth of granulation tissue,provide the basis of successful skin grafting.(2)After ischemic preconditioning on the subcutaneous vascular net free skin , strengthening the capacity of resistance to ischemia, and can make skin more new capillaries on the edge, speeding up the process of capillary, thereby accelerate the growth of granulation tissue.(3)Experimental observation show that through basal skin blood supply is blocked ,the subculous vascular net free skin can still live according to the peripheral revascularization establishment.which has important clinical significance to the success rate of transplant,and can provide experimental evidence and clinical basis for clinical operation.