Figure 5.

Systemic injections of zVAD promote hair cell survival. Chickens were given daily simultaneous injections of (1) zVAD (1.5 mg/kg) and streptomycin (1200 mg/kg), (2) streptomycin alone, or (3) saline alone for 5 d. Hair cells (either stereocilia bundles or calretinin ⁺ cells) were quantified in 10,000 μm² regions from the central region of the horizontal canal and both the extrastriolar and striolar areas of the utricle. For stereocilia bundle densities, means (±SD) represent three sampled regions per organ in the horizontal canal. In the utricle, two regions per organ of the extrastriolar region and one region per organ in the striolar region were sampled. For calretinin densities, means (±SD) represent two regions sampled in each horizontal canal. In the utricle, six regions per organ in the extrastriolar region and four regions per organ in the striolar region were sampled. More hair cells were present in both sensory organs after 5 d of treatment of zVAD/streptomycin, when compared with animals receiving streptomycin alone. Significantly fewer hair cells were present in all sampled regions of zVAD/streptomycin-treated animals when compared with animals receiving saline alone (p < 0.01). n = 3–5 organs.