X-Ray Irradiation of the Inner Ear of the Guinea Pig An Electron Microscopic Study of the Degenerating Outer Hair Cells of the Organ of Corti

Abstract

The inner ear of guinea pigs was irradiated with single doses of 7000 R X-rays. An electron microscopic study of the organ of Corti was performed after 1¹/₂ 3, 4, and 6 hours.

Changes were noticed in the outer hair cells of the two basal coils while the inner hair cells, the outer hair cells of the two apical coils and the supporting cells were normal.

The first changes were observed in the nuclei and consisted of clumping of the chromatin and the inter-chromatinic substance. Later the nuclei became pyc-notic.

In the cytoplasm the early changes were: increase of peculiar elements of interconnected smooth and rough endoplasmic reticulum; various mitochondrial alterations; increase in the number of glycogen-like granules; increase in the number and size of lyso-some-like bodies in the apical portions of the cells and the appearance of sequesters of small cytoplasmic areas delimited by a double or a single membrane. Severely altered cells appeared shrunken.

At later stages cell debris with an electron transparent matrix and numerous vacuoles were observed.

No signs of phagocytosis were noticed. The elimination of the degenerated elements is presumably due to autolysis.