Keywords :
Adenoviridae; Animals; Animals, Newborn; Apoptosis/genetics; Brain-Derived Neurotrophic Factor/pharmacology; Cell Survival; Cells, Cultured; Cisplatin/toxicity; Genes, bcl-2/physiology; Genetic Vectors; Hair Cells, Auditory/drug effects/pathology; Membrane Potential, Mitochondrial/drug effects/genetics; Neomycin/toxicity; Nerve Degeneration/genetics; Neurons/drug effects/pathology; Oxidative Stress; Rats; Rats, Wistar; Simplexvirus; Spiral Ganglion/drug effects/pathology
Abstract :
[en] OBJECTIVE: To test the hypothesis that bcl-2 prevents oxidative stress-induced apoptosis of auditory sensory cells in explants of the organ of Corti and dissociated cell cultures of the spiral ganglion. METHODS: Organ of Corti explants and dissociated spiral ganglion cell cultures obtained from 3-day-old (P3) rats or adult spiral ganglion cell cultures from 28-day-old (P28) rats were transduced with vectors containing a human bcl-2 gene. Cultures were then exposed to neomycin, cisplatin or subjected to withdrawal of neurotrophin supplementation. Outcome measures included hair cell and neuron counts, mitochondrial membrane potential and a histological measure of apoptosis. RESULTS: Expression of bcl-2 in the organ of Corti explants and neuronal cell cultures provided a significant level of protection against cell death. Bcl-2 expression in the organ of Corti explants also protected mitochondria from loss of membrane potential and blocked an early step in the commitment of hair cells to apoptosis. CONCLUSION: Expression of bcl-2 in cochlear tissues protects sensory cells from a variety of insults that have been demonstrated to damage the inner ear.
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