成熟か牛コルチ器支持細胞の修復機転に関する細胞動態的研究 外有毛細胞障害か牛における支持細胞の核ＤＮＡ合成から

Abstract

3H-thymidine autoradiography in vivo was carried out on normal mature mice, whose organs of Corti were securely damaged by Nitrogen Mustard-N-oxide (nitromin). The cell kinetics of supporting cells of the organ of Corti were examined and relation between these changes and mechanisms of supporting cells to maintain the organ of Corti was discussed in this paper. A few grains in various kinds of supporting cells in S stage, which were not found in control mice without nitromin injection, were discovered. Those were detected in Hensen's cell, Deiters' cell, Claudius' cells, and inner phalangeal cell. Mitosis was seen in one Claudius' cell in addition. Therefore some supporting cells seem to be able to synthesize DNA and proliferate in the acutely damaged organ of Corti even in mature cochlea and those in G0 stage begin to go around cell cycle as occasion demands. Although labelled supporting cells decreased over time, the portion of supporting cell is likely to change in proportion as the extension of damage in the organ of Corti. If this new dynamic change of cell kinetics in the acutely damaged organ of Corti means the reaction to repair the organ of Corti, the supporting cells seem to have a reasonable role to maintain the organ of Corti including repairment of reticular lamina.