上皮根鞘细胞表面超微结构及牙根发育中上皮根鞘增殖力的变化

The surface ultrastructure of epithelial root sheath cells and their proliferative ability during tooth root development

目的：观察体外培养的上皮根鞘细胞超微结构及牙根发育中上皮根鞘增殖力的变化。方法：体外培养大鼠上皮根鞘细胞，扫描电镜观察。制备出生后5d、7-8d和15d的SD大鼠下颌磨牙石蜡切片，增殖细胞核抗原，检测免疫染色。结果：上皮根鞘细胞表面有许多微绒毛，细胞间连接紧密。牙根发育中上皮根鞘增殖力有序变化。结论：上皮根鞘细胞具有典型的上皮细胞表面结构特性。牙根发育中上皮根鞘有序断裂与其增殖力变化有关。

AIM： To observe the surface ultrastructure of rat epithelial root sheath （ERS）cell and to examinethe proliferative ability of ERS during tooth root development. METHODS ： ERS cells were cultured, identified by immunoeytoehemieal staining with anti-cytokeratin 14 antibody, and then observed by scanning electron microscope （SEM）. Mandibular molars of postnatal （PN） 5 days, 7-8 days and 15 days SD rats were made into paraffin-embedded sections. The activity of ERS cell proliferation was examined immunohistochemically by proliferative cell nuclear antigen （PCNA）. RESULTS：ERS cells were cobblestone-shaped, positively stained for cytokeratin 14. Many microvilli could be observed on ERS cell surface. ERS cells were tightly connected with each other through many digitations. The proliferative ability of ERS ehangeds regularly during tooth root development. CONCLUSION： ERS cell possesses typical surface characteristics of epithelial cells. The proliferative ability change of ERS probably results in its disruption.