Effect of Systemic Steroid on the Olfactory Epithelium Injured by 3-Methylindole in Mice

ABSTRACT

BACKGROUND AND OBJECTIVES: Various chemicals can affect the function of olfaction and steroids have been used for the treatment of olfactory dysfunction. In this study, we investigated the effect of chronic dexamethasone treatment on olfactory epithelium injured by 3-methylindole (3-MI). SUBJECTS AND METHODS: 0.75 mg/kg of dexamethasone and 0.15 mL of normal saline were administered to each of the 12 mice belonging to the experimental and control group respectively every other day from 1 week, before a single intraperitoneal administration of 175 mg/kg 3-MI, to 4 weeks after 3-MI injection. Three mice from each group were sacrificed every week, and olfactory epithelium was examined after H & E and immunohistochemical staining. RESULTS: On H & E staining, the height of the olfactory epithelium and the polarity of the cells showed no difference between the two groups. On olfactory marker protein (OMP) staining, the number of OMP-immunoreactive (IR) olfactory receptor cells was significantly increased in the experimental groups from 2 and 4 weeks after 3-MI injection compared with the control group. On proliferating cell nuclear antigen (PCNA) staining, PCNA-IR basal cells were significantly reduced in groups that received dexamethasone from 2 weeks to 3 weeks after injection compared with the control group. CONCLUSION: Dexamethasone shows no protective effect in early necrosis of olfactory epithelium by 3-MI, but showed positive effect on the regeneration of the olfactory receptor cells of olfactory epithelium.