Nutbrown M, Randall V A
Department of Biomedical Sciences, University of Bradford, U.K.
J Invest Dermatol. 1995 Jan;104(1):90-4. doi: 10.1111/1523-1747.ep12613579.
Although the ultrastructure of the dermal-epidermal junction has been well characterized, little is known about the junctions between the dermal papilla and the surrounding epithelial cells of the hair bulb, or between the connective tissues and the epithelial cells on the outside of the hair follicle. Because the dermal papilla plays a major role in controlling the hair follicle, we also examined the ultrastructure of the potentially important dermal papilla-epithelial junction in normal scalp anagen follicles. The dermal-epidermal junction in skin was a trilaminar basement membrane characterized by the anchoring points of hemidesmosomes and tonofilaments in keratinocytes. In the hair follicle, the junction that separated the dermal papilla and epithelial cells was a trilaminar basement membrane, but relatively few putative anchoring points were seen. These were similar to modified dermal-melanocyte junctions, in which the intercellular cytoplasmic filaments do not come together at an attachment plaque, the laminar components tend to be thinner, and the anchoring fibrils beneath the lamina densa are fewer. A trilaminar membrane also was interposed between the connective and epithelial tissues on the outside of the follicle, but nothing that resembled a hemidesmosome or any other type of anchoring structure was seen. The difference in structure of the junctional complex between skin and hair follicles probably reflects the relatively permanent state of the epidermis, compared to the dynamic processes involved during the anagen phase of the hair follicle.
尽管真皮 - 表皮交界处的超微结构已得到充分表征，但对于毛乳头与毛囊球周围上皮细胞之间的连接，或结缔组织与毛囊外部上皮细胞之间的连接却知之甚少。由于毛乳头在控制毛囊方面起主要作用，我们还研究了正常头皮生长期毛囊中潜在重要的毛乳头 - 上皮连接的超微结构。皮肤中的真皮 - 表皮交界处是一个三层基底膜，其特征在于角质形成细胞中半桥粒和张力丝的附着点。在毛囊中，分隔毛乳头和上皮细胞的连接是一个三层基底膜，但可见的假定附着点相对较少。这些类似于改良的真皮 - 黑素细胞连接，其中细胞间细胞质丝不在附着斑处聚集，层状成分往往更薄，并且致密层下方的锚定原纤维较少。在毛囊外部的结缔组织和上皮组织之间也插入了一个三层膜，但未见到类似半桥粒或任何其他类型锚定结构的东西。皮肤和毛囊之间连接复合体结构的差异可能反映了表皮相对永久的状态，与毛囊生长期所涉及的动态过程相比。
