Pasche F, Mérot Y, Carraux P, Saurat J H
Department of Dermatology, University Hospital, Geneva, Switzerland.
J Invest Dermatol. 1990 Sep;95(3):247-51. doi: 10.1111/1523-1747.ep12484847.
Close relationships between Merkel cells (MC) and nerve endings (NE) exist in the adult mouse. Because MC may serve as targets for the ingrowth of NE during embryogenesis, the purpose of the present study was to analyze the relationship between MC and NE during embryogenesis. Frozen tissue from whisker pads and backs of NMRI mouse embryos (12-17 d gestational age) were studied by double-labeling indirect immunofluorescence (IIF) with a cytokeratin monoclonal antibody that recognizes MC and with a neurofilament anti-serum. Such an approach allowed the analysis of a large number of MC (up to 5000), thus yielding quantitative data. At day 12 of gestational age, no MC were observed by IIF. From day 13 to 17, the number of MC, as well as their association with NE, progressively increased. On day 13, only 57% of whisker pad MC were NE associated, whereas by day 17, 95% were NE associated. These results were confirmed by electron microscopic (EM) observations. On the back, the same chronologic relationship between MC and NE was observed, but was later in the course of embryogenesis. There was also a time- and zone-dependent increase in MC association with NE in the epidermal zones studied (isthmic, parafollicular, interfollicular). These observations 1) establish the time course of MC and NE contacts during embryogenesis in the mouse epidermis, 2) show that MC are present in the epidermis and appendages before NE reach the epithelium, and 3) support the hypothesis that MC could act as targets for the growing NE.
在成年小鼠体内，默克尔细胞（MC）与神经末梢（NE）之间存在紧密联系。由于在胚胎发育过程中MC可能是NE向内生长的靶标，因此本研究的目的是分析胚胎发育过程中MC与NE之间的关系。通过使用识别MC的细胞角蛋白单克隆抗体和神经丝抗血清进行双标记间接免疫荧光（IIF），研究了NMRI小鼠胚胎（妊娠12 - 17天）的须垫和背部的冷冻组织。这种方法能够分析大量的MC（多达5000个），从而得出定量数据。在妊娠第12天，通过IIF未观察到MC。从第13天到第17天，MC的数量以及它们与NE的关联逐渐增加。在第13天，须垫中只有57%的MC与NE相关，而到第17天，这一比例为95%。这些结果通过电子显微镜（EM）观察得到了证实。在背部，观察到MC与NE之间存在相同的时间顺序关系，但在胚胎发育过程中出现得较晚。在所研究的表皮区域（峡部、滤泡旁、滤泡间），MC与NE的关联也存在时间和区域依赖性增加。这些观察结果1）确定了小鼠表皮胚胎发育过程中MC与NE接触的时间进程，2）表明在NE到达上皮之前，MC就已存在于表皮和附属器中，3）支持了MC可能作为生长中的NE的靶标的假说。
