Acoustic overstimulation-induced apoptosis in fibrocytes of the cochlear spiral limbus of mice

Fibrocytes of the spiral limbus are thought to play a significant role in maintaining ion homeostasis in the cochlea. The present study measured physiological and morphological changes in spiral limbus of mice in response to noise exposure. 6-week-old male C3H/HeJJcl mice were exposed to octave-band noise (120 dB SPL) for 2 h and evaluated at a series of times thereafter, up to 8 weeks. Permanent hearing loss resulted in the mice, as assessed by auditory brainstem response (ABR) recordings. The fibrocytes loss was found in the spiral limbus of the apical turn, which has been proved to be induced by apoptosis. These results suggest that noise exposure might result in apoptosis of fibrocytes in spiral limbus, which suggest a mechanism for noise-induced hearing loss.