Uptake of gadolinium and dexamethasone in rat inner ear and facial nerve using different administrations

Abstract

Background

The pathway by which drugs are injected subcutaneously behind the ear to act on the inner ear has not been fully elucidated.

Objectives

To compare the uptake of gadopentetate dimeglumine (Gd-DTPA) and dexamethasone (Dex) in the cochlea and facial nerve of rats following different administrations.

Materials and methods

Magnetic resonance imaging was applied to observe the distribution of Gd-DTPA in the facial nerve and inner ear. We observed the uptake of Dex after it was injected with different methods.

Results

Images of the intravenous (IV) and intramuscular (IM) groups showed that the bilateral cochlea of the rat was visualized almost simultaneously. While in the left post-auricular (PA) injection group, it was asynchronous. The maximum accumulation (C_max) of the Gd in the left facial nerve of the PA group (35.406 ± 5.32) was substantially higher than that of the IV group (16.765 ± 3.7542) (p < .01).

Conclusions

Compared with systemic administration, PA has the advantages of long Gd and Dex action time and high accumulation concentration to treat facial nerve diseases.

Significance

The distribution of Gd and Dex in the inner ear and facial nerve of rats following PA injection might be unique.

背景

药物通过耳后皮下注射作用于内耳的途径尚未得到完全阐明。

目的

在不同给药后, 比较大鼠的耳蜗和面神经中钆喷酸二葡胺 (Gd-DTPA) 和地塞米松(Dex)的吸收。

材料与方法

应用磁共振成像观察Gd-DTPA 在面神经和内耳中的分布。 我们观察用不同的方法注射 Dex 后的吸收情况。

结果

静脉注射(IV)组和肌内注射(IM)组的图像显示大鼠双侧耳蜗几乎可以同时观察到, 而在左耳后(PA)注射组中, 却是异步的。 PA组左侧面神经Gd最大累积量(Cmax)(35.406 ± 5.32) 显著高于 IV 组 (16.765 ± 3.7542) (p < .01)。

结论

与全身给药相比, PA具有Gd和Dex作用时间长、积累浓度高的优点, 可治疗面神经疾病。

意义

PA注射后大鼠内耳和面神经中Gd和Dex的分布可能是独特的。

Keywords:

• Magnetic resonance imaging
• post-auricular injection
• facial nerve
• inner ear diseases
• Gd-DTPA
• dexamethasone

Acknowledgements

The authors would like to thank Magnetic Resonance Imaging Research Center of Peking University for the assistance with MRI.

Author contributions

Xing Jin: overall design, data processing and text writing of the study. Yixu Wang: design of the study and revision of the article. Liyuan Zhang: partial conduction of animal experiments. Hongwei Zheng: design of the partial study and revision of the article. Xin Ma: design of the partial study and revision of the article. Lisheng Yu: overall design of the study and revision of the article. Maoli Duan: design of the study and revision of the article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China (2101000556) and Capital Health Research and Development of Special Fund (2151000034).