Spiral ganglion cell morphology in guinea pigs after deafening and neurotrophic treatment.

Spiral ganglion cell morphology in guinea pigs after deafening and neurotrophic treatment.
Hear Res. 2013 Jan 26;
Authors: van Loon MC, Ramekers D, Agterberg MJ, de Groot JC, Grolman W, Klis SF, Versnel H
Abstract
It is well known that spiral ganglion cells (SGCs) degenerate in hair-cell-depleted cochleas and that treatment with exogenous neurotrophins can prevent this degeneration. Several studies reported that, in addition, SGC size decreases after deafening and increases after neurotrophic treatment. The dynamics of these cell size changes are not well known. In a first experiment we measured size, shape (circularity) and intracellular density of SGCs in guinea pigs at various moments after deafening (1, 2, 4, 6, and 8 weeks) and at various cochlear locations. In a second experiment, the effect of treatment with brain-derived neurotrophic factor (BDNF) on SGC morphology was investigated at various cochlear locations in deafened guinea pigs. We found that SGC size gradually decreased after deafening in the basal and middle cochlear turns. Already after one week a decrease in size was observed, which was well before the number of SGCs started to decrease. After BDNF treatment SGCs became noticeably larger than normal throughout the cochlea, including the middle and apical turns, whereas an effect on survival of SGCs was primarily observed in the basal turn. Thus, both after deafening and after neurotrophic treatment a change in size occurs be...

Source: Hearing Research - January 26, 2013 Category: Audiology Authors: van Loon MC, Ramekers D, Agterberg MJ, de Groot JC, Grolman W, Klis SF, Versnel H Tags: Hear Res Source Type: research