Facultad de Medicina, Instituto de Investigación en Discapacidades Neurológicas, Universidad de Castilla-La Mancha Albacete, Spain.
Front Aging Neurosci. 2014 Mar 5;6:29. doi: 10.3389/fnagi.2014.00029. eCollection 2014.
Age-related hearing loss (ARHL) is one of the most frequent sensory impairments in senescence and is a source of important socio-economic consequences. Understanding the pathological responses that occur in the central auditory pathway of patients who suffer from this disability is vital to improve its diagnosis and treatment. Therefore, the goal of this study was to characterize age-related modifications in auditory brainstem responses (ABR) and to determine whether these functional responses might be accompanied by an imbalance between excitation and inhibition in the cochlear nucleus of Wistar rats. To do so, ABR recordings at different frequencies and immunohistochemistry for the vesicular glutamate transporter 1 (VGLUT1) and the vesicular GABA transporter (VGAT) in the ventral cochlear nucleus (VCN) were performed in young, middle-aged and old male Wistar rats. The results demonstrate that there was a significant increase in the auditory thresholds, a significant decrease in the amplitudes and an increase in the latencies of the ABR waves as the age of the rat increased. Additionally, there were decreases in VGLUT1 and VGAT immunostaining in the VCN of older rats compared to younger rats. Therefore, the observed age-related decline in the magnitude of auditory evoked responses might be due in part to a reduction in markers of excitatory function; meanwhile, the concomitant reduction in both excitatory and inhibitory markers might reflect a common central alteration in animal models of ARLH. Together, these findings highlight the suitability of the Wistar rat as an excellent model to study ARHL.
年龄相关性听力损失（ARHL）是衰老过程中最常见的感觉障碍之一，也是重要的社会经济后果的来源。了解患有这种残疾的患者中枢听觉通路中发生的病理反应对于改善其诊断和治疗至关重要。因此，本研究的目的是表征听觉脑干反应（ABR）的年龄相关性变化，并确定这些功能反应是否可能伴随着耳蜗核中兴奋和抑制之间的失衡。为此，在年轻、中年和老年雄性 Wistar 大鼠中进行了不同频率的 ABR 记录以及腹侧耳蜗核（VCN）中囊泡谷氨酸转运蛋白 1（VGLUT1）和囊泡 GABA 转运蛋白（VGAT）的免疫组织化学染色。结果表明，随着大鼠年龄的增加，听觉阈值显著增加，ABR 波的幅度显著降低，潜伏期延长。此外，与年轻大鼠相比，老年大鼠 VCN 中的 VGLUT1 和 VGAT 免疫染色减少。因此，观察到的听觉诱发电响应幅度随年龄的下降可能部分归因于兴奋性功能标志物的减少；同时，兴奋性和抑制性标志物的同时减少可能反映了 ARHL 动物模型中常见的中枢改变。总之，这些发现强调了 Wistar 大鼠作为研究 ARHL 的优秀模型的适用性。
