C57BL黒マウスにおけるメラノサイトの胎生学的分化に関する電顕的研究

Abstract

Based on light microscopic studies, many investigators, such as Zimmermann and Becker maintained the neural crest theory concerning the embryonic origin of the melanocyte in the skin. In order to investigate this problem on ultrastructural level, the present study was undertaken and concerned with the ultrastructural comparison between the melanocytes found in skins of fetus and newborn black mice of C57BL, from 10 days in utero to 5 days post partum and the neural crest cells as well as the neuroblast-like cells that were found in a mouse embryo of C57BL and contained premelanosomes and melanosomes. The study revealed a small number of melanocytes in the dermis of 18 days and 20 days in utero and in the epidermis of 1 day and 5 days post partum. In addition, the cells probably identified as so-called agranular dendritic cells were found in the epidermis of 19 days in utero, and 3 days and 5 days post partum. The ultrastructural similarities between the neural crest cells displaying melanosome formation and the melanocytes found in the skin seemed to indicate that the former might differentiate into the latter, moving through the mesenchyme.