[Effect of sildenafil on morphology to noise-induced hearing loss in guinea pigs]

To study the effects of sildenafil on morphology to noise-induced hearing loss in guinea pigs.

Guinea pigs were randomly divided into control group, noise exposure group and the sildenafil treatment group, 12 in each group. a week after white noise exposure of 110 dB, sildenafil (10 mg/kg x d) and NS (4 ml/kg x d) were injected into guinea pigs of the sildenafil treatment group and noise exposure group respectively for four continuous weeks. ABR thresholds were measured respectively prior to the experiment, 1 week post-noise, 1, 2 and 4 weeks post-drugs, the changes of cochlea hair cells were also observed with a scan electron microscope (SEM) and light microscope.

The ABR threshold shifts in the sildenafil treatment group were significantly fewer than that in the noise exposure group. SEM showed that hear hair of the inner and outer hair cells in noise exposure group displayed mess, fusion and imperfections. In the sildenafil treatment group, the hair cells displayed slight pathological changes, there wasn't significant differents comparied with normal group. The number of OHCs were relatively stable in the normal group, while the obvious OHC loss was observed in other groups. There was significant difference among the three groups, however, the OHC loss in the sildenafil treatment group was not significantly different to that in the noise exposure (P > 0.05).

Sildenafil can significantly protect against noise-induced hearing loss.