Acoustic Trauma Increases Cochlear and Hair Cell Uptake of Gentamicin
Figure 2
Prolonged sound exposure increased gentamicin uptake in OHCs.
Gentamicin (200 mg/kg) was injected i.p. for 30 minutes following an 18-hour WBN exposure over 3 days (6 hours per day, 86 dB SPL). Increased gentamicin immunofluorescence was generally observed in basal sound-exposed OHCs (B) compared to control (non-sound exposed) animals (A). Scale bar in A = 20 µm. C: The immunofluorescence intensity of OHC cuticular plates from either middle coils (circle) or basal coils (square) were increased in 3 of 4 animals after chronic moderate sound exposure (p<0.05, paired t-test). Immunoprocessing for each batch of animals were carried out simultaneously for each pair-wise comparison. Chronic moderate sound exposure did not disrupt hair bundle morphology determined by phalloidin labeling (D, red), nor nuclei integrity by DAPI staining (E, blue); green, anti-gentamicin IgG. Scale bar = 20 µm. F: This sound exposure paradigm produced a temporary elevation in hearing thresholds (n = 6) that largely recovered within 4 weeks. Error bar is s.e.m. *p<0.05, **p<0.01.