Figure 7.

Intracochlear perfusion with D-JNKI-1, but not with D-TAT-empty or inactive JNKI-1-mut peptides, prevented the hearing loss induced by exposure to the acoustic trauma paradigm. A, Shown are the functional recoveries over time of CAP threshold shifts, for a 8 kHz pure tone from contralateral control cochleae (black circles) and cochleae perfused with artificial perilymph alone (i.e., 0 μm; white circles) or with artificial perilymph containing either 10 μm (white squares) or 100 μm (white triangles) D-JNKI-1 peptide. Note the initial rapid phase of recovery within the first 2 d, followed by a slower recovery phase in all animals. D-JNKI-1 both accelerated and improved the final functional recovery of the CAP. Time-response data have been fitted to exponential curves. B, The dose-dependent effects of D-JNKI-1 at 6 d after acoustic trauma with hearing loss at 8 kHz expressed as the percentage of recovery is shown. Dose–response data were then fitted to a curve using a nonlinear least-square logistic equation. The Boltzman equation was used for fitting sigmoid curves. The EC₅₀ was calculated as 2.31 μm. C, A comparison a 10 μm D-TAT-empty-perfused right cochleae (white circles) with contralateral unperfused left cochleae (black circles) in the same animals exposed to acoustic trauma (n = 3) showed no significant differences (i.e., both ears showed both the same level and pattern of hearing loss). D, A comparison of a 10 μm JNKI-1-mut-perfused right cochleae (black circles) with contralateral unperfused left cochleae (white circles) in the same animals exposed to acoustic trauma (n = 3) showed similar patterns of hearing losses.