Tectorial membrane repair in the quail following multiple exposures to intense sound.

Adult quail were exposed one, two or three times to an intense octave band noise. Birds were sacrificed 0 or 14 days after the last exposure and their ears processed for scanning electron microscopy (SEM). SEM observations demonstrated a patch lesion in every ear at 0 and 14 days after exposure. In the single-exposed ear immediately after noise, the lesion lacked any tectorial membrane (TM). At 14 days of recovery, the site of injury was covered by a partially regenerated TM (referred to as the honeycomb). However, the patterns of TM damage and repair varied among the twice- and thrice-exposed papillae. At 0 days after exposure, the multiple-exposed ear displayed a lesion with two segments. In one portion the TM was missing, and in the other portion the TM was present as one or two honeycomb layers. Fourteen days later, a new honeycomb was observed underneath the remaining honeycomb. These results suggest that the quail is able to repeatedly repair its TM following multiple noise exposures.