Smith L T, Sakai L Y, Burgeson R E, Holbrook K A
Department of Biological Structure, University of Washington, Seattle 98195.
J Invest Dermatol. 1988 Apr;90(4):480-5. doi: 10.1111/1523-1747.ep12460951.
The ontogeny and composition of the dermal-epidermal junction (DEJ) in developing human embryonic and fetal skin was studied at progressive stages of gestation by immunofluorescence microscopy and immunocytochemistry using transmission electron microscopy (TEM). The DEJ of embryonic skin at 5 weeks estimated gestational age (EGA) was a simple basement membrane zone limited to the basal cell plasma membrane, lamina lucida, and lamina densa. A network of reticular collagen fibrils (reticular lamina) was deposited beneath the lamina densa by 6 weeks. Coincident with the onset of increased complexity in epidermal and dermal structure, at the time of the embryonic to fetal transition, the DEJ displayed additional components that were markers of maturation. At 7-8 weeks EGA, fine filamentous structures extended from the DEJ into the reticular lamina. By 9 weeks EGA hemidesmosomes and banded anchoring fibrils were recognizable, although distributed sparsely at the DEJ. With increasing gestational age, these structures displayed greater electron density and structural completeness. By the end of the first trimester, the DEJ appeared ultrastructurally similar to that of mature skin. Weak immunofluorescent labeling demonstrated the presence of type VII collagen at the DEJ by 8 weeks EGA. From 10-12 weeks EGA immunofluorescent labeling of the DEJ for type VII collagen was distinctly punctate, while immunoperoxidase labeling observed by TEM was linear, continuous, and sublamina densa in position. With ongoing gestation the immunofluorescent labeling became increasingly stronger at the DEJ. Thus, type VII collagen was present at the DEJ in the zone immediately beneath the lamina densa, before the appearance of mature anchoring fibrils but coordinate with the appearance of fine filamentous, unbanded structures, and appeared to increase with the development and accumulation of anchoring fibrils.
利用透射电子显微镜（TEM）通过免疫荧光显微镜和免疫细胞化学技术，在妊娠的不同阶段研究了发育中的人类胚胎和胎儿皮肤中真皮-表皮交界处（DEJ）的个体发生和组成。估计妊娠年龄（EGA）为5周时的胚胎皮肤DEJ是一个简单的基底膜区，仅限于基底细胞质膜、透明层和致密层。到6周时，在致密层下方沉积了网状胶原纤维网络（网状层）。在胚胎向胎儿过渡时，随着表皮和真皮结构复杂性的增加，DEJ显示出其他成熟标志物成分。在EGA 7-8周时，细丝状结构从DEJ延伸到网状层。到EGA 9周时，半桥粒和带状锚定纤维虽然在DEJ处分布稀疏，但已可识别。随着胎龄增加，这些结构显示出更高的电子密度和结构完整性。到妊娠第一个月末，DEJ的超微结构与成熟皮肤相似。弱免疫荧光标记显示在EGA 8周时DEJ处存在VII型胶原。从EGA 10-12周开始，DEJ对VII型胶原的免疫荧光标记明显呈点状，而TEM观察到的免疫过氧化物酶标记呈线性、连续，且位于致密层下方。随着妊娠进展，DEJ处的免疫荧光标记越来越强。因此，VII型胶原在致密层下方紧邻区域的DEJ处存在，早于成熟锚定纤维的出现，但与细丝状、无带状结构的出现同步，并且似乎随着锚定纤维的发育和积累而增加。
