ヒト膀胱移行上皮の構築的微細構造

Abstract

1)成人正常膀胱粘膜を割断法による走査型電子顕微鏡(SEM)観察, 透過型電子顕微鏡(TEM)観察をおこない, 細胞構成より重層上皮と考えた.2)表層細胞の内腔側表面はさざ波状で, microridgeが存在し, 真の微絨毛は認めず, あっても短小で, 通常は結節様突起というべきものであった.3)腔側細胞膜は二重から成る3層構造を呈するが, 従来から言われているasymmetric unit membrane構造は部分的であった.4)表層細胞, 中層細胞, 基底細胞の各細胞間の結合は表層より基底部に向い複雑になっている.どの細胞の表面にも微絨毛はみず, 存在しても短小のものであった.TEM像の微絨毛様構造はひだ状, 隔壁状突起やmicroridgeの横断面と考えた

Human urinary bladder mucosa, confirmed to be normal by cystoscopic, histologic and bacteriologic examination, were obtained from four patients at prostatectomy and from two patients at an anti-VUR procedure. The luminal surface and the three dimensional architecture of the bladder mucosa were observed by scanning electron microscopy (SEM) after cryofracture of specimen and by transmission electron microscopy (TEM). The epithelium consists of superficial, intermediate and basal cells, and SEM and TEM showed that it was stratified. Intermediate cells reached the basal lamina by slender cytoplasmic processes but superficial cells were not directly in contact with the basal lamina. No pleomorphic or long microvilli were observed but short microvilli or granular protrusions were sparsely seen on the luminal surface of superficial cells. SEM of cryofractured surfaces revealed that cells from each cell layer were in contact with cellular junctions such as ridges, plicated projections and septum-like walls. Their junctions were more complicated with increasing depth of the cell layer. No pleomorphic or long microvilli were observed on any cell surface of the intermediate or basal cell layer. Under TEM, however, these junctional structures of ridges, plicated projections and septal walls appeared to be microvilli under TEM. Microvilli-like structures on TEM, therefore, have to be carefully distinguished from real microvilli. Careful observation is required when the presence of cells covered with microvilli is described as a sign of malignancy.