慢性神经营养治疗后聋耳蜗螺旋神经节神经元的存活和功能。
Spiral ganglion neuron survival and function in the deafened cochlea following chronic neurotrophic treatment.
机构信息
Bionics Institute, Daly Wing, St. Vincent's Hospital, Fitzroy, Victoria 3065, Australia.
出版信息
Hear Res. 2011 Dec;282(1-2):303-13. doi: 10.1016/j.heares.2011.06.007. Epub 2011 Jul 6.
Cochlear implants electrically stimulate residual spiral ganglion neurons (SGNs) to provide auditory cues for the severe-profoundly deaf. However, SGNs gradually degenerate following cochlear hair cell loss, leaving fewer neurons available for stimulation. Providing an exogenous supply of neurotrophins (NTs) has been shown to prevent SGN degeneration, and when combined with chronic intracochlear electrical stimulation (ES) following a short period of deafness (5 days), may also promote the formation of new neurons. The present study assessed the histopathological response of guinea pig cochleae treated with NTs (brain-derived neurotrophic factor and neurotrophin-3) with and without ES over a four week period, initiated two weeks after deafening. Results were compared to both NT alone and artificial perilymph (AP) treated animals. AP/ES treated animals exhibited no evidence of SGN rescue compared with untreated deafened controls. In contrast, NT administration showed a significant SGN rescue effect in the lower and middle cochlear turns (two-way ANOVA, p < 0.05) compared with AP-treated control animals. ES in combination with NT did not enhance SGN survival compared with NT alone. SGN function was assessed by measuring electrically-evoked auditory brainstem response (EABR) thresholds. EABR thresholds following NT treatment were significantly lower than animals treated with AP (two-way ANOVA, p = 0.033). Finally, the potential for induced neurogenesis following the combined treatment was investigated using a marker of DNA synthesis. However, no evidence of neurogenesis was observed in the SGN population. The results indicate that chronic NT delivery to the cochlea may be beneficial to cochlear implant patients by increasing the number of viable SGNs and decreasing activation thresholds compared to chronic ES alone.
人工耳蜗通过电刺激残余螺旋神经节神经元(SGN)为极重度聋患者提供听觉线索。然而,由于耳蜗毛细胞的缺失,SGN 逐渐退化,可用于刺激的神经元越来越少。已证实外源性提供神经营养因子(NTs)可防止 SGN 退化,并且与短暂失聪(5 天)后进行慢性耳蜗内电刺激(ES)相结合,也可能促进新神经元的形成。本研究评估了在耳聋后两周开始的为期四周的 NT(脑源性神经营养因子和神经营养素-3)与 ES 联合治疗的豚鼠耳蜗的组织病理学反应,将其与 NT 单独治疗和人工外淋巴(AP)治疗的动物进行比较。与未治疗的耳聋对照相比,AP/ES 治疗的动物没有表现出 SGN 挽救的迹象。相比之下,NT 给药与 AP 治疗的对照动物相比,在下和中耳蜗转(双向方差分析,p < 0.05)中表现出显著的 SGN 挽救作用。与单独 NT 相比,ES 与 NT 联合使用并未增强 SGN 存活。通过测量电诱发听觉脑干反应(EABR)阈值来评估 SGN 功能。与用 AP 治疗的动物相比,NT 治疗后的 EABR 阈值显著降低(双向方差分析,p = 0.033)。最后,使用 DNA 合成的标志物研究了联合治疗后诱导神经发生的潜力。然而,在 SGN 群体中没有观察到神经发生的证据。结果表明,与单独慢性 ES 相比,向耳蜗持续递送 NT 可能通过增加存活的 SGN 数量并降低激活阈值,使耳蜗植入患者受益。