Effect of ginkgo biloba and dexamethasone in the treatment of 3-methylindole-induced anosmia mouse model.
BACKGROUND
Olfactory loss is a challenging disease. Although glucocorticoid is sometimes used for the treatment of anosmia, it has been reported that it potentiated neural damage in the early phase of treatment. This study is designed to identify the effect of ginkgo biloba, an antioxidant that acts as a free radical scavenger, in the treatment of olfactory injury aggravated by dexamethasone.


METHODS
Anosmia mouse model was induced by i.p. injection of 3-methylindole (3-MI). Twenty-five mice were divided into one control group without anosmia and four anosmia treatment groups (given treatments of dexamethasone and/or ginkgo biloba). The effects of treatment were evaluated by behavioral test, Western blot, and immunohistochemistry 2 weeks after 3-MI injection.


RESULTS
Induction of anosmia was confirmed by behavioral tests. The thickness and cell number of olfactory neuroepithelium were decreased more significantly in the dexamethasone treatment group than in the combination treatment group. The expression of olfactory marker protein (OMP) in olfactory epithelium was more decreased also in the dexamethasone treatment group than in the combination treatment group. The expression of OMP was decreased significantly in the olfactory bulbs of anosmia groups but there were no differences between the anosmia treatment groups.


CONCLUSIONS
Dexamethasone treatment was associated with further deterioration of olfactory injury by 3-MI and it was recovered by combination treatment of dexamethasone and ginkgo biloba. The antioxidant effect of ginkgo biloba might play a role in restoration of olfactory loss and it was effective only when oxidative stress is maximized by dexamethasone.
Lee
Chul Hee
CH
Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
Mo
Ji-Hun
JH
Shim
Seung Hee
SH
Ahn
Jung-Min
JM
Kim
Jeong-Whun
JW
D000818:Animals; D000975:Antioxidants / Q000627:therapeutic use*; D001522:Behavior, Animal / Q000187:drug effects; D015153:Blotting, Western; D002452:Cell Count; D003907:Dexamethasone / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D020441:Ginkgo biloba; D005938:Glucocorticoids / Q000627:therapeutic use*; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D046569:Neuroepithelial Cells / Q000187:drug effects / Q000473:pathology; D000857:Olfaction Disorders / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D009830:Olfactory Bulb / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051842:Olfactory Marker Protein / Q000096:biosynthesis; D009831:Olfactory Mucosa / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D009832:Olfactory Nerve / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy / Q000379:methods*; D028321:Plant Preparations / Q000627:therapeutic use*; D012862:Skatole / Q000633:toxicity; D016896:Treatment Outcome
D000975:Antioxidants; D005938:Glucocorticoids; D051842:Olfactory Marker Protein; C497598:Omp protein, mouse; D028321:Plant Preparations; D003907:Dexamethasone; D012862:Skatole