Article
Effect of erythropoietin on cultured spiral ganglion cells
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Published: | August 8, 2007 |
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Introduction: Loss of hair cells with consecutive degeneration of spiral ganglion cells (SGC) is the main characteristic of hearing loss. The benefit achieved by the use of cochlear implants depends among other factors on the number of surviving SGC. It has been recently demonstrated that erythropoietin (EPO) attenuates apoptosis of ganglion cells. The aim of the present study is therefore to test the effect of EPO on SGC.
Methods: Spiral ganglion cells were isolated from neonatal rats (p3-5). Dissected and dissociated SGC were cultured for 48 and 72 hours at 37°C and with supplementation of either 2.5 or 5 ng/ml EPO. Surviving SGC, neurite length and cell soma diameter were determined. Results were compared with the effect of brain-derived neurotrophic factor (BDNF) (50 ng/ml). Furthermore, the effect of EPO combined with BDNF was investigated.
Results: The low concentrations of EPO investigated in this study had no effect on SGC. However, in combination with BDNF they further increased survival and neurite length. The mean neurite length of 236 µm (BDNF alone) was increased to 308 µm (BDNF + 5 ng EPO) and 362 µm (BDNF +2.5 ng EPO) after the cultivation period of 48 hours and to 571 nm (BDNF + 5 ng EPO) and 647 µm (BDNF +EPO 2.5 ng/ml) after 72 hours.
Conclusion: Erythropoietin has only a minor protective effect on survival of SGC. However, EPO led to an increased neutrite outgrowth on surviving SGC.