Morphological and functional protective effects of H₂S against NIHL.

<p>A–F: Scanning electron micrographs of the basilar membrane. Evident stereocilia bundle defects (white stars) were observed in control (D, E) and PPG (H, I) groups. The stereocilia bundles in the NaHS group appeared relatively normal (F, G). G–I: Cochlear sensory epithelia surface preparation in control (A), NaHS (B) and PPG (C) groups. OHC loss and evident stereocilia bundle defects are indicated (red arrows). J: Percent OHC loss in each row. The loss was localized primarily in the third row and the posterior second row. OHC loss in the NaHS group is less than control. The PPG exhibited the highest loss percentage. K: Mean post-surgical ABR threshold shifts at different time points after noise exposure. The ABR threshold shift demonstrated a significant decrease on the 14th day in the NaHS group (47.00±2.60 dB SPL) compared to the control group (56.11±2.32 dB SPL) and the PPG group (56.88±2.82 dB SPL) (P<0.05).