Hamamoto Y, Nakajima T, Ozawa H
First Department of Oral and Maxillofacial Surgery, Niigata University School of Dentistry, Japan.
Arch Histol Cytol. 1989 Mar;52(1):61-70. doi: 10.1679/aohc.52.61.
The morphogenesis of the epithelial rests of Malassez in rat molars was studied by light and electron microscopy. The epithelial islands immediately after disintegration of the Hertwig's root sheath consisted of a few irregularly shaped cells with scanty rough endoplasmic reticulum, which were surrounded in portions by disrupted basal lamina. Close topographic relationships between the epithelial cells and mesenchymal cells of the dental sac were often observed in this period. After thirty days of age, the epithelial cells started to form ovally shaped epithelial islands consisting of four or five cells, but collagen fibrils still remained in the intercellular spaces. Vacuoles containing collagen fibrils were occasionally observed in the cytoplasm of the epithelial cells during this period in association with an acid phosphatase positive reaction. In more mature rat molars, the epithelial islands were characterized by an increased number of epithelial cells, only rarely observed collagen fibrils in the cytoplasm and the intercellular spaces, and an almost complete lining of basal lamina. The results indicate that the phagocytosis of collagen fibrils by the epithelial cells is a crucial step in the formation of the epithelial rests. The possibility is suggested that interactions with mesenchymal cells of the dental sac and regeneration of the basal lamina may also contribute to the epithelial rest formation.
采用光镜和电镜研究了大鼠磨牙中马拉瑟上皮剩余的形态发生。赫特维希根鞘解体后立即出现的上皮岛由一些形状不规则、粗面内质网稀少的细胞组成，这些细胞部分被破坏的基膜包围。在此期间，常观察到上皮细胞与牙囊间充质细胞之间紧密的地形关系。30日龄后，上皮细胞开始形成由四五个细胞组成的椭圆形上皮岛，但细胞间隙中仍有胶原纤维残留。在此期间，上皮细胞的细胞质中偶尔可见含有胶原纤维的空泡，并伴有酸性磷酸酶阳性反应。在更成熟的大鼠磨牙中，上皮岛的特征是上皮细胞数量增加，细胞质和细胞间隙中很少观察到胶原纤维，基膜几乎完全形成。结果表明，上皮细胞对胶原纤维的吞噬作用是上皮剩余形成的关键步骤。提示与牙囊间充质细胞的相互作用和基膜的再生也可能有助于上皮剩余的形成。
