Connective tissue changes due to long-term ultraviolet exposure : Structural and biochemical studies

揭示了人类和动物皮肤在时间老化和光老化之间真皮结缔组织改变的差异。材料与方法。使用人皮和动物皮。人体皮肤：健康男性（年轻31人，老年32人）和牛皮癣患者（年轻2人，老年1人，用PUVA治疗）暴露在阳光或紫外线下并受到保护的皮肤。动物皮肤：无毛大鼠皮肤（5uvb （1med）暴露13个月，对照组5个月）。对一些健康男性在日光照射和防护区域的皮肤进行超声成像。从上述所有人和动物身上获得皮肤活检标本，并进行光镜和电子显微镜处理，并对弹性纤维进行氨基酸分析。超声检查，在图像上，真皮层位于表皮白线和下面的脂肪组织之间。老年人的真皮比年轻人薄，日晒区比防护区薄。-我们可以在白线下方观察到一个黑色区域，该区域显示了一个相对均匀的、无回声的结构，只有老年人暴露在阳光下的区域。组织学上，在日晒、puva处理和UVB处理的皮肤中，（在一些健康和puva处理的人群中）可见到胶原纤维增生并向下延伸至基底层真皮层，胶原纤维排列不规则增厚，增加和增厚，不同程度的弹性纤维受损，淀粉样蛋白沉积。在受保护皮肤和对照组皮肤中，可见一层排列规则的胶原纤维薄的基底层，弹性纤维增厚但未受损。未见淀粉样蛋白沉积。弹性纤维中的氨基酸分析表明，与年轻人的皮肤相比，暴露在阳光下的皮肤中谷氨酸、天冬氨酸、丝氨酸、丝氨酸和赖氨酸含量较高，而保护皮肤中的谷氨酸、天冬氨酸、丝氨酸和赖氨酸含量较低。

The difference in dermal connective tissue alteration between chronological aging and photoaging using human and animal skin has been disclosed.Materials and Methods. Human skin and animal skin was used. Human skin : sun or UV exposed and protected skin of healthy men(31 young and 32 old)and patients with psoriasis(2 young and one old, treated with PUVA). Animal skin : hairless rats skin(5 UVB(1 MED)exposed for 13 months and 5 control). Ultrasonic skin images were obtained from sun-exposed and protected areas of some healthy men.Skin biopsy specimens were obtained from all men and animals mentioned above, and were processed for light and electron microscopy, and for amino acid analysis for elastic fibers.Results. Ultrasonically, on the images, the dermis was clearly located between white line of the epidermis and underlying fatty tissue. The dermis was thinner in aged persons than young persons, and that of sun-exposed area wag thinner than that of protected area. - One can observe below the white line, a black zone showing a relatively homogeneous, non-echogenic structure in only sun-exposed area of aged persons.Histologically, in sun-exposed, PUVA-treated and UVB exposed skin, multiplication and down ward to the dermis of the basal lamina, irregularly arranged thickened collagen fibers, increased and thickened, various degrees of damaged elastic fibers, and amyloid deposits(in some healthy and PUVA-treated persons)were seen. In protected skin or control rat skin, a layer of basal lamina, regularly arranged, thin collagen fibers, thickened but not damaged elastic fibers, were seen. No amyloid deposits were seen.Analysis of amino acid in elastic fibers showed glutamic and asparatic acid, sreonine, serine, and lysine were higher in sun-exposed skin, while they were lower in protected skin when compared with that in young adults' skin.