Bixenstine Paul J, Maniglia Mauricio P, Vasanji Amit, Alagramam Kumar N, Megerian Cliff A
Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University, University Hospitals of Cleveland, Cleveland, Ohio 44106, USA.
Laryngoscope. 2008 Jul;118(7):1217-23. doi: 10.1097/MLG.0b013e31816ba9cd.
The mechanistic association between endolymphatic hydrops (ELH) and hearing loss (HL) is unclear. Although ELH severity has been shown to correlate in some studies with HL, injury of vital structures, including hair cells and the cochlear nerve, have failed to demonstrate correlation with ELH severity. The goal of this study is to evaluate the hypothesis that spiral ganglion cell degeneration is the principle pathologic site of ELH-related cochlear injury, correlates with ELH severity, and is most profound in the apical region.
Surgical induction of ELH in the guinea pig model was followed by histologic confirmation of ELH and subsequent correlation with segmental spiral ganglion cell densities.
Guinea pigs (N = 14) were subjected to unilateral ELH induction and killed after 4 to 6 months. ELH severity and spiral ganglion densities were obtained using computer-aided morphometric analysis. Densities were normalized by calculating a spiral ganglion degeneration index (DI) for each animal.
The apical spiral ganglion demonstrated significantly greater degeneration than that noted in the basal spiral ganglion (DI: 1.93 vs. 1.13; P = .004). The degree of spiral ganglion degeneration in the apex correlates well with a total hydrops index (P = .006) and an apical hydrops index (P = .003). Basal spiral ganglion degeneration however, does not correlate well with hydrops severity (total hydrops index: P > .05; basilar hydrops index: P > .05).
ELH-related pathology appears to focus initially on the apical spiral ganglion and the degree of deterioration correlates well with the severity of ELH. These findings mirror some reports in the human condition, and imply that the mechanism of cochlear injury in ELH and secondary dysfunction appears to be a neural toxicity that begins in the apex of the cochlea.
内淋巴积水（ELH）与听力损失（HL）之间的机制关联尚不清楚。尽管在一些研究中已表明ELH严重程度与HL相关，但包括毛细胞和耳蜗神经在内的重要结构损伤与ELH严重程度并未显示出相关性。本研究的目的是评估以下假设：螺旋神经节细胞变性是ELH相关耳蜗损伤的主要病理部位，与ELH严重程度相关，且在顶端区域最为明显。
在豚鼠模型中手术诱导ELH，随后通过组织学确认ELH，并将其与节段性螺旋神经节细胞密度进行相关性分析。
14只豚鼠接受单侧ELH诱导，4至6个月后处死。使用计算机辅助形态计量分析获得ELH严重程度和螺旋神经节密度。通过计算每只动物的螺旋神经节变性指数（DI）对密度进行标准化。
顶端螺旋神经节的变性明显大于基底螺旋神经节（DI：1.93对1.13；P = 0.004）。顶端螺旋神经节的变性程度与总积水指数（P = 0.006）和顶端积水指数（P = 0.003）密切相关。然而，基底螺旋神经节变性与积水严重程度的相关性不佳（总积水指数：P>0.05；基底积水指数：P>0.05）。
ELH相关病理似乎最初集中在顶端螺旋神经节，其退变程度与ELH严重程度密切相关。这些发现与人类疾病的一些报道相符，表明ELH中耳蜗损伤和继发性功能障碍的机制似乎是始于耳蜗顶端的神经毒性。
