Background: Despite the importance of olfactory function, no effective medications have been identified to treat olfactory disorders. This study was performed to evaluate the functional recovery of olfaction damaged by 3-methylindole (3MI) in a mouse model with hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins).
Methods: In a randomized placebo-controlled trial, 24 healthy female BALB/c mice (aged 9-10 weeks and weighing 18-20 g each) were randomly allocated to statin-treated or control groups. Olfactory loss was induced by i.p. injections of 3MI. Atorvastatin (10 mg/kg) or normal saline was then administered per os with a gastric tube for 3 weeks. The effects of treatment were evaluated by food-finding tests and Western blot analysis.
Results: Both groups showed complete losses of olfactory function 1 week after 3MI injection. Three weeks after 3MI injection, 9 of the 12 mice in the statin-treated group (75%) passed a food-finding test, in which they were able to find the food within 3 minutes, at least two times out of three trials. However, only two mice in the control group (16.6%) passed the food-finding test, and this difference was statistically significant (p = 0.004; chi-square test). The expression level of the olfactory marker protein was also elevated in the statin-treated group (p = 0.030; Wilcoxon rank sum test).
Conclusion: Statins are associated with recovery of olfaction after 3MI injection in a mouse model.