Denèfle J P, Zhu Q L, Lechaire J P
Biol Cell. 1987;59(3):219-26. doi: 10.1111/j.1768-322x.1987.tb00533.x.
The dermis of the frog skin (Rana esculenta) displayed a remarkable organization of vertical and horizontal tracts. Vertical thick tracts connected the dermal Stratum spongiosum with the subcutaneous tissue. Horizontal thin tracts were found alongside and contiguous to them. The thick tracts were sheathed by collagen fibrils of the Stratum compactum which were vertically oriented (i.e. parallel to the axes of the tracts) according to the horizontal and orthogonal arrangement of the collagen bundles of the Stratum compactum. The thin tracts devoid of collagenous sheath were formed by clear spaces between superimposed collagen bundles of the dermal Stratum compactum. On vertical sections, the thick tracts were seen to contain fibronectin (FN), detected by indirect immunoperoxidase. Continuous vertical FN lines were centred in these tracts. On horizontal sections, a clear zone around these FN-centred lines was also sheathed by FN. The thick tracts contained flattened pigmentary cells and fibroblasts; these cells were FN-outlined. The thin tracts contained patches of FN and FN-outlined fibroblasts. In culture, in vertical thick tracts, both pigmentary cells and fibroblasts disappeared when antiserum to FN was added to the culture medium. This suggested that thick tracts were pathways allowing pigmentary cells to move upward or downward between their usual upper dermal and lower subcutaneous localizations. Fewer fibroblasts were found in the thin tracts in the presence of antiserum to FN.
食用蛙（Rana esculenta）皮肤的真皮呈现出显著的垂直和水平束状结构。垂直的粗束将真皮海绵层与皮下组织相连。在它们旁边并与之相邻发现了水平的细束。粗束被致密层的胶原纤维包裹，这些胶原纤维根据致密层胶原束的水平和正交排列垂直定向（即与束的轴平行）。缺乏胶原鞘的细束由真皮致密层叠加的胶原束之间的空隙形成。在垂直切片上，通过间接免疫过氧化物酶检测发现粗束中含有纤连蛋白（FN）。连续的垂直FN线位于这些束的中心。在水平切片上，围绕这些以FN为中心的线的透明区域也被FN包裹。粗束中含有扁平的色素细胞和成纤维细胞；这些细胞由FN勾勒出轮廓。细束中含有FN斑块和由FN勾勒出轮廓的成纤维细胞。在培养中，在垂直的粗束中，当向培养基中加入抗FN血清时，色素细胞和成纤维细胞都会消失。这表明粗束是允许色素细胞在其通常的上部真皮和下部皮下定位之间向上或向下移动的途径。在存在抗FN血清的情况下，细束中发现的成纤维细胞较少。
