Effect of hypodynamia on structure of vestibular apparatus in Japanese quail chicks: light microscopy

The model for studying the effects of simulated microgravity on the bird organism is hypodynamia. The aim of this study was to investigate the influence of chronic hypodynamia on the structure of the vestibular apparatus in Japanese quail by light microscopy. Morphological changes in the sensory epithelium of chicks reared under hypodynamia from 1 to 42 days of age were evaluated. The differences of shape and arrangement of hair cells in sensory epithelium macula utriculi and the dilatations on their basal parts were found in birds exposed to hypodynamia on day 14 and 42 compared to control. The results confirmed that hypodynamia has specific impact on developmental processes in Japanese quail and indicated that similar damage of inner ear sensory epithelium could be developed in chicks hatched and reared in conditions of real weightlessness during the space flight.