Background

Vestibular hair cell loss and its role in balance disorders are not yet completely understood due largely to the lack of precise hair cell damage protocols.

New method

Our damage protocol aims to selectively remove type I hair cells in a way that produces consistent and predictable lesions that can be used for reliable inter-animal and inter-group comparison in balance research. This objective is achieved by transtympanic injection of gentamicin on both the round window membrane and oval window over a fixed time period followed by thorough washing.

Results

We achieved nearly total and consistent loss of type I hair cells at 94 % for the crista ampullaris of the lateral semicircular canal (LSC) and 86 % for the utricular macula with negligible loss of type II hair cells at 4% for the crista ampullaris of the LSC and 6% for the utricular macula. While the vestibular function was compromised in the relevant study group, this group had a zero mortality rate with no significant suppression of body weight gain.

Comparison with existing methods

Gentamicin is typically administered via intraperitoneal systemic injection or, more recently, transtympanic injection. The intraperitoneal method is simple, but mortality rate is high. The transtympanic injection method produces ototoxic damage but with inconsistent lesion size. This inconsistency prevents reliable comparisons among animals.

Conclusions

This protocol employs a transtympanic injection method which selectively targets type I hair cells for removal in the vestibular epithelia in a time-dependent manner, uniformly damages vestibular function, and causes uniform hair cell loss.

中文翻译：

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时间依赖性鼓膜给药庆大霉素可稳定去除豚鼠前庭终末器官的毛细胞

背景

由于缺乏精确的毛细胞损伤方案，目前尚未完全了解前庭毛细胞的丧失及其在平衡失调中的作用。

新方法

我们的损伤方案旨在以产生一致且可预测的病变的方式选择性地去除I型毛细胞，可用于在平衡研究中进行可靠的动物间和群体间比较。通过在固定时间段内在圆窗膜和卵圆窗上经鼓膜注射庆大霉素来进行彻底清洗，即可达到该目的。

结果

对于外侧半规管（LSC）的壶腹，我的I型毛发细胞几乎完全一致地丢失，为94％；对于输卵管黄斑，86％的II型毛细胞损失为4％。 LSC和6％的黄斑部黄斑。尽管相关研究组的前庭功能受到损害，但该组的死亡率为零，而体重增加并未受到明显抑制。

与现有方法的比较

庆大霉素通常通过腹膜内全身注射或更近期地通过鼓膜注射给药。腹膜内方法简单，但死亡率高。鼓室注射法产生耳毒性损害，但病变大小不一致。这种不一致阻止了动物之间可靠的比较。

结论

该协议采用鼓室注射方法，该方法选择性地靶向I型毛发细胞，使其以时间依赖的方式在前庭上皮细胞中去除，均匀破坏前庭功能，并导致均匀的毛细胞丢失。