Affordable Access

deepdyve-link
Publisher Website

A Time Limit for Initiating Anti-Inflammatory Treatment for Improved Olfactory Function after Head Injury.

Authors
  • Kobayashi, Masayoshi1
  • Tamari, Kengo1
  • Kitano, Masako1
  • Takeuchi, Kazuhiko1
  • 1 Department of Otorhinolaryngology-Head and Neck Surgery, Mie University Graduate School of Medicine , Mie, Japan . , (Japan)
Type
Published Article
Journal
Journal of Neurotrauma
Publisher
Mary Ann Liebert
Publication Date
Feb 15, 2018
Volume
35
Issue
4
Pages
652–660
Identifiers
DOI: 10.1089/neu.2017.5316
PMID: 29117762
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

We previously reported that treatment with an anti-inflammatory drug, specifically a steroid, is effective in improving recovery during the acute phase of head injury. Clinically, however, patients with head injury usually become aware of their olfactory loss several weeks or months after the injury, which may be a critical factor in poor recovery from olfactory dysfunction. This raises an important question: When should steroid administration begin in order to achieve optimum improvement of olfactory dysfunction? The present study was designed to reveal the time limit for starting anti-inflammatory treatment for better improvement of post-traumatic olfactory dysfunction. Olfactory nerve transection (NTx) was performed in olfactory marker protein (OMP)-tau-lacZ mice and subcutaneous injections of dexamethasone sodium phosphate for 5 consecutive days was started at 7, 14, 28, and 42 days after the NTx (7-, 14-, 28-, and 42-day time-points). Histological assessment of olfactory nerve recovery in the olfactory bulb was made at 5, 14, and 42 days after the start of drug treatment. Olfactory function assessments using both an olfactory avoidance behavioral test and evoked potential testing also were performed. Animals treated at 7 days post-injury had less injury-associated tissue with fewer astrocytes and macrophages and better histological and functional nerve recovery, compared with control mice. However, those treated at 14, 28, or 42 days post-injury did not show significant histological or functional differences between saline control and treatment groups. These findings suggest that an anti-inflammatory treatment using steroids for traumatic olfactory dysfunction may be effective if started at least by 7 days, but may be ineffective at 14 days or later after head injury.

Report this publication

Statistics

Seen <100 times