Electron microscopic changes of keratohyalin granules during the freezing and thawing procedure.

After 3-day-old rat skins were treated by freezing and thawing procedures, small empty spaces were formed both in keratohyalin granules and in the cytoplasm of the granular cells. When the skin specimens thus treated were further incubated in 50 mM Tris-HCl buffer, pH 8.6, for 15 min, keratohyalin granules were solubilized, leaving electron dense rims. Small electron dense or less dense particles were detaching from these rims. Cell membranes were also disrupted at various regions. Desmosomal structures in the stratum granulosum cells were all preserved.