【作者】 毛秀立；

【导师】 魏泓；

【作者基本信息】 西南大学 ， 动物学， 2007， 硕士

【摘要】 背景异体和异种皮肤是临床上替代自体皮肤治疗大面积烧伤的主要敷料，但异体(异种)皮肤抗原性强，特别是新鲜皮肤，还带有大量的菌污染，皮肤移植后的强烈免疫排斥反应和菌污染往往会导致皮肤过早的坏死。中波紫外线(UVB)，波长280—320nm，它可降低免疫原性，可应用于器官移植的前处理，降低受者对移植物的排斥反应和移植物的抗宿主反应，但UVB是否有灭菌作用，仍未有报道。因此，紫外照射是降低移植皮肤的抗原性、延长移植皮肤存活提供简单、快捷的途径。但是将UVB降低免疫原性应用于皮肤移植的研究缺乏系统的研究，且多大剂量可以达到最理想的效果仍不清楚。研究目的和意义本课题以不同剂量UVB照射离体巴马香猪皮肤为实验材料，研究不同剂量UVB对皮肤的免疫原性、带菌量、活力等指标的影响，旨在寻找可以降低免疫原性、带菌量少、活力较高的UVB照射剂量，为延长移植皮肤存活奠定理论基础。方法与结果1．免疫原性检测1．1淋巴细胞增殖实验UVB以剂量依赖的方式抑制皮肤的免疫原性。30J／cm~2UVB照射时，有轻微抑制，抑制率为14.3％；60J／cm~2UVB照射时，抑制率为42.9％；360J／cm~2UVB照射时，达到最大抑制率，抑制率为99.9％。1．2 ATP酶染色郎格汉细胞(Langerhans cell，LC)新鲜皮肤LC ATP酶染色呈棕黑色，树突状；UVB处理后，LC树突减少，甚至消失。UVB处理后LC数量较新鲜皮有显著下降，并且随照射剂量的增加LC数量逐渐下降。UVB处理后皮肤的免疫原性与皮肤中LC数量呈正相关。2．带菌量检测UVB具有抑菌作用。随着UVB剂量的增大，皮肤中的带菌量减少，UVB达到本研究中最大剂量180J／cm~2时，皮肤中仍有带菌量。3．UVB对皮肤的损伤作用用MTT法检测UVB预处理的皮肤活性实验表明，UVB剂量在0—90J／cm~2范围内，皮肤的活力随剂量的增大而减小，当UVB剂量增加到90—360J／cm~2，皮肤的活力又先升后降。结论UVB具有抑菌作用，可以降低皮肤的免疫原性，但对皮肤有损伤作用；UVB以剂量依赖的方式抑制皮肤的免疫原性，且皮肤的免疫原性与UVB照射后皮肤中LC数量呈正相关；UVB剂量为30-60J／cm~2时，离体皮肤免疫原性低，皮肤损伤小，且带菌量低，可作为异体(异种)皮肤移植的实验基础数据。更多还原

【Abstract】 BackgroundAllogeneic and xenogeneic skin are the regular dressings in the treatment of large burn wounds as the substitute of autologous skin. However, both allogeneic and xenogenic skins face strong immune rejection which may result in early necrosis in skin grafts shortly after transplantation. Radiation with Ultraviolet Radiation B (UVB) ranging between 320-280nm wavelength has been found to be capable of reducing graft immunogenicity to some degree in addition to disinfection, and recognized as a potential and simple method to reduce skin antigenicity and further to prolong its survival in the procedure of sin grafting. However, a detailed study is required to find out the most proper radiation dose by which the skin antigenicity can be effectively reduced without remarkable viability loss. ObjectiveThis study has investigated the effects of different dosees of UVB radiation on the immnogenicity, disinfection and viability of BAMA miniature pig skins, in order to find out a proper dose of UVB radition with which the skin immunogenicity can be reduced with no remarkable viability loss.Methods and results1. Tests of immunogenicity1.1 Lymphocyte proliferation testUVB reduces the immunogenicity of skin in a dose-dependent manner. In 30J/cm2, the reduction rate was 14.3%; In 60J/cm2, it was 42.9%; The largest reduction rate (99.9%) was observed when the dose was 360J/cm2.1.2 Langerhans cell (LC) countsThe LCs in fresh skin were stained to be black in a shape like that of dendritic cells. The LC counts in skin was remarkably reduced or even completely disminished after UVB radiation. The LC counts in skin was reduced by UVB radiation in a dose-dependent manner. There was a positive correlation between the immunogenicity and the number of LC in the skin treated by UVB.2. Germ-carrying detectionUVB has a function of bacteriostasis. The germ-carrying of skin became less with the augmentation of UVB dose. However, there was still some germ even when the largest dose of UVB was used.3. UVB caused damages to skinWe investigated the viability of skin treated by UVB by MTT method. Result showed that skin viability decreased when the UVB dose was augmented from 0 to 90 J/cm~2,. However, the viability was observed to rise then decreased when the UVB dose was in the range of 90—360 J/cm~2.ConclusionsUVB has the function of bacteriostasis; UVB reduced skin immunogenicity in a dose-dependent manner; The number of LC became less when the dose of UVB was augmented, and there was a positive correlation between UVB dose and skin immunogenicity; UVB radiation resulted in damages to the skin to some degrees. The immunogenicity, damages and germ-carrying of the skin were all on the lowest levels when the UVB dose was in the range of 30-60 J/cm~2. The results in this study laid down the experimental foundation for better Allogeneic or xenogenic skin grafting.更多还原