Experimental Study On The Structure And Expression Of A-SMA Of The Skin And Basical Capsule Of The One-way Expansion And Conventional Expansion

Objective:By microscope and transmission electron microscope, the experiment was designed to observed the ultrastrural changes of the skin tissue and the substrate capsule both of the one-way tissue expansion and the conventional expansion.The distribution and expression ofα—SMA was measured by immunohistochemistry and the result was used to compare the percentage ofα—SMA positive cells.The aim of the study is to understand the characteristic and merit of the one-way expansion,to investigate the contracted mechanisms of expanded skin.Methods:From June 2006 to December 2007 in our department,24 cases treated with the second operation on the face or the neck to get out the skin soft-tissue expander.24 cases were divided into 2 groups,and one group is one-way expansion group and the other is conventional expansion group.5 cases came from the full-thickness grafts transplantation made up the normal skin group.The tissue samplesin each group were collected from the full-thickness skin and the substrate capsule of the expander bed..The tissue was made into paraffin sevial sections and stained with hematoxylin-eosin respectively.All deta was analyzed by SPSS 13.0 version for windows and quantitative deta were expressed by Mean Standard Deviation。The dermal ultrastrural changes were observed by electroscope and transmission electron microscope.The expression ofα—SMA in dermis of each group skin had been anglicized by immunohistochemistry and the result was used to for image analyzing.RESULTS:(1)Two different expanded ways had the same effects showed that the distant between epidermal cells became much more larger and the thickness increased significantly.There was no significant difference in the thickness of the epidermis between the one-way expanded group and the conventional expanded group(P＞0.05)(2)The thickness of the dermal became much more thinner and the arrangements of collagen fibers were increased and loosened.A large amount of fibroblasts came into being and distributed into derma.A part of these fibroblasts with a functional activity transferred into myfibloblasts. (3)By immunohistochemistryα—SMA was examined out in myfibloblasts cytoplasm and small arterial wall smooth muscle. There was no significant difference the percentage of activity cells whichα—SMA the fibroblasts changed into myfibloblasts (P＞0.05).(4)A large amount of collagen and fibroblasts,new small arterial and capillaries were developed in the capsule of the base expander.Conclution:(1)After expansion histomorphological changes of soft tissue are similar in the ultrastructure changes and microstructure.There is no foundation in histological manifestation that one-way expansion had much more serious damage to the skin tissue than conventional expansion.(2)The stimulation from expansion may promote the profliferation of fibroblasts and have the functional activity.Part of these fibroblasts changed into myfibloblasts and had the ability to contract.The retraction of expanded skin was similar.The difference of the percentage ofα—SMA positive cells between two groups showed no significance.There was no significant difference showed that much more fastly lead to much more serious retraction (3)A large amount of collagen and fibroblasts,new small arterial and capillaries were developed in the capsule of the base expander.