Low-dose Gamma Irradiation Effects on Labyrinthine Development in Vitro

Abstract

The 13th and 16th gestational day inner ear anlagen, respectively, were exposed after explantation to an organ culture system to low-dose gamma irradiation with a 2 Gy single dose. The explants were thereafter cultured in vitro for 8 vs. 5 days to an age corresponding to birth in vivo. The explants were analysed with regard to gross morphology and at the light and electron microscopic levels. The 13th gestational day inner ear anlage showed malformations of the gross shape. The gross morphology of the 16th gestational day inner ear explant was unaffected. Irradiated specimens showed a delayed development in general as compared with controls.

A defective cytodflerentiation of hair cells was observed at the ultrastructural level. Sensory hair fusion occurred, the sensory hair rootlets were poorly developed as also was the cuticle. Nerve terminals were not identified. The observations in the present in vitro study are in agreement with corresponding earlier published in vivo investigations. The organ culture model can thus be used for irradiation induced selective effects on labyrinthine development.

Key Words:

• inner ear
• embryonic development
• in vitro
• ionizing irradiation
• morphology