Imayama S, Braverman I M
Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut.
Am J Pathol. 1989 May;134(5):1019-25.
To provide a morphologic basis for a better understanding of the "aging" of human skin, the authors studied the three-dimensional arrangement and chronological alterations of the fibrous components of the connective tissue using rats aged 2 weeks to 24 months with a new technique for scanning electron microscopy. These studies showed that with postnatal growth there was a dynamic rearrangement of the collagen and elastic fibers: an ordered arrangement of mature collagen bundles was attained by producing a distortion of the elastic fiber meshwork of relatively straight fibers. During adulthood, there was a subsequent tortuosity of the distorted elastic fibers coupled with an incomplete rebuilding of the elastic fiber network, laid down in a form to interlock with the collagen bundles. These changes provide a model for explaining manifestations of aged skin, such as laxity, sagging, and wrinkling. The tortuously fixed elastic fibers imply that they have been stretched and have lost their original elasticity and ability to restitute short and straight. Interlocking of both collagen and elastic fibers should disturb the two independent fibrous systems, as would normally be the case, and thus decrease tissue compliance.
为了更好地理解人类皮肤的“老化”提供形态学依据，作者使用一种新的扫描电子显微镜技术，对2周龄至24月龄大鼠结缔组织纤维成分的三维排列和时间变化进行了研究。这些研究表明，随着出生后的生长，胶原纤维和弹性纤维发生了动态重排：通过使相对直的弹性纤维网变形，实现了成熟胶原束的有序排列。成年期，扭曲的弹性纤维随后出现弯曲，同时弹性纤维网络的重建不完全，其排列形式与胶原束相互交错。这些变化为解释老年皮肤的表现，如松弛、下垂和皱纹，提供了一个模型。弹性纤维的弯曲固定意味着它们已经被拉伸，失去了原来的弹性和恢复短直状态的能力。胶原纤维和弹性纤维的交错应该会干扰这两个通常独立的纤维系统，从而降低组织顺应性。
