Effects of acoustic trauma on the auditory system of the rat: The role of microglia.

摘要: Exposure to loud, prolonged sounds (acoustic trauma, AT) leads the death of both inner and outer hair cells (IHCs OHCs), neurons spiral ganglion degeneration auditory nerve. The nerve (8cn) projects three subdivisions cochlear nuclei (CN), dorsal nucleus (DC) anterior (VCA) posterior (VCP) ventral (VCN). There is anatomical physiological evidence for plastic reorganization in denervated CN after AT. Anatomical findings show axonal sprouting synaptogenesis; physiologically there an increase spontaneous activity suggesting circuitry. mechanisms underlying this plasticity are not understood. Recent data suggest that activated microglia may have a role facilitating addition removing trauma-induced debris. In order investigate roles subsequent AT we exposed animals bilateral noise sufficient cause massive cell death. We studied four groups at different survival times: 30 days, 60 6 months 9 months. used silver staining examine time course pattern degeneration, immunohistochemistry label CN. found degenerating fibers days was close geographic overlap between microglia, consistent with scavenger microglia. At longest time, were still silver-stained but very little overlapping regions. were, however, surrounding brainstem cerebellar white matter.