Experimental Study On The Repair Of Skin Defect By Transplantation Of Tissue-engineered Skin

Extensive defect of skin is one of common and intractable diseases in clinic, people desired to find ways to resolve the problem from early ago. Tissue engineering is the product of co-development and combination of modern cell biology, biomaterial science, and engineering. The tissue engineering technology possible will ravel out it in future. Because different type skin defect has different cause, understanding of defective types seems to be instructive to the development of treatments. In my study, two types of animal models are established, tissue-engineered dermis and tissue-engineered composited skin was cultured in vitro and transplanted in the two types of animal model. The experiment contains four main parts:1. The establishment of acute skin injury model in swine with aseptic wounds. On the back of swines, the skin in each side of spinal column were removed with scalpel to achieve a full-thickness skin circular defect wound .The defect wounds were designed 3cm, 4cm, 5cm in diameter and randomly devided into three groups. All the wounds were covered with petrolatum aseptic gauze Two weeks after injury, contraction of wound area of the three groups separately were 97.47 + 8.15%,67.25 ±7.13 % and 41.52 + 3.81 %. The results proved the defect wounds that have diameter of 5cm were ideal wounds for the investigation.2. The establishment of diabetic ulcer model in swine. Yueke swines were injected alloxan through vein, glucose level of fasting blood samples were exceeded 1.2g/l after 48h. A kind of press apparatus of prepared by ourselves was installed on the each side of spinal column. Ulcers were created in a 20cm2 region of dorsal skin in swine by compressing skin under different pressures. Different degree ulcer occurred in groups of 12h and groups of 24h in 1st to 7th day after removal and continue existed with no obvious sign of heal in the 7th to14th day, in the 14th to 21st day, the ulcers began to contract but didn't heal completely. The animal model can simulate clinical diabetic skin ulcer and the method of establishing the model is easy and reliable.3. Transplanted the full-thickness and dermis tissue engineering skin to repair full-thichness skin defect of swine and compared it with autograft skin and blank through observing their developments and their histological changements. The investigation of post-operation proved transplanted the full-thickness tissue engineering skin had double-deck structure of dermis and epidermis, so its histology was almost similar to natural skin, dermis tissue engineering skin was transplanted after two weeks post-operation, the net of blood vessels and structure of fiber was recovery gradually. Engineered skin has no obvious rejection. We have affirmed the tissue-engineered skin has good histocompatibility and can betransplanted into the full-thickness loss wounds.4. The transplantation experiment of full-thickness tissue engineering skin torepair diabetic skin ulcer, contrasting with autograft and blank. Firstly, ulcer wounds were prepared by the method of experiment 2; then infection was controlled, the full-thickness tissue engineering skin was transplanted in the skin wounds of swine finally. The grafts adhered tightly to the wounds and grew well; the rate of survival was no obvious difference between tissue engineering skin...