Schwartz E, Cruickshank F A, Perlish J S, Fleischmajer R
Department of Dermatology, Mount Sinai School of Medicine, New York, New York 10029.
J Invest Dermatol. 1989 Jul;93(1):142-6. doi: 10.1111/1523-1747.ep12277386.
Chronic exposure of the skin to sunlight results in severe dermal connective tissue damage that is characterized by the basophilic degeneration of collagen and the accumulation of an elastotic material. The aim of this study was to identify changes in collagen (the major structural protein of the skin) in ultraviolet irradiated mouse skin using immunochemical and biochemical techniques. Specific antibodies directed against the aminopropeptide of type III procollagen were used in immunofluorescence and immunoblotting studies. Immunofluorescent staining of irradiated and nonirradiated mice skin showed that the aminopropeptide of type III procollagen was distributed throughout the dermis in a pattern similar to that observed for type I collagen. Extracts of irradiated (5 and 10 weeks) and nonirradiated skins were then subjected to immunoblotting techniques. Levels of pN alpha 1, type III procollagen (measured by radioimmunoassay) were reduced in the extracts prepared from skins of mice that were irradiated for 5 and 10 weeks. Immunoelectron microscopy verified the loss of pN alpha 1 type III procollagen in irradiated skin. Collagen fibers of nonirradiated skin demonstrated normal labeling with antibody directed against the aminopropeptide of type III procollagen. In contrast, collagen fibers of 10 week irradiated skin failed to label with this antibody. The pN alpha 1 type III collagen is known to coat type I collagen fibers of normal skin. Therefore, its absence from the surface of type I collagen fibers of irradiated skin may play a role in the development of the elastotic material.
皮肤长期暴露于阳光下会导致严重的真皮结缔组织损伤，其特征为胶原蛋白的嗜碱性变性和弹性物质的积累。本研究的目的是使用免疫化学和生化技术，确定紫外线照射的小鼠皮肤中胶原蛋白（皮肤的主要结构蛋白）的变化。针对III型前胶原氨基端前肽的特异性抗体用于免疫荧光和免疫印迹研究。对照射和未照射的小鼠皮肤进行免疫荧光染色显示，III型前胶原氨基端前肽在真皮中的分布模式与I型胶原相似。然后对照射（5周和10周）和未照射皮肤的提取物进行免疫印迹技术分析。在照射5周和10周的小鼠皮肤提取物中，通过放射免疫测定法测得的III型前胶原pNα1水平降低。免疫电子显微镜证实照射皮肤中III型前胶原pNα1缺失。未照射皮肤的胶原纤维用针对III型前胶原氨基端前肽的抗体显示正常标记。相比之下，照射10周的皮肤胶原纤维未能用该抗体标记。已知pNα1 III型胶原覆盖正常皮肤的I型胶原纤维。因此，其在照射皮肤的I型胶原纤维表面缺失可能在弹性物质的形成中起作用。
