The effect of Ginkgo biloba on the expression of intermediate-early antigen (c-fos) in the experimentally induced anosmic mouse.
OBJECTIVE
Treatment of olfactory dysfunction is very difficult and has limited modality. Treatment with steroids has been used in patients with olfactory dysfunction but the side effects of steroid need to be weighed against its potential benefits. In the present study, the effect of systemic administration of dexamethasone and EGb 761 on damage to olfactory mucosa produced by zinc sulfate was examined. Expression of the immediate-early antigen (IEG), c-fos, in the olfactory bulb and piriform cortex was used to determine the effects of treatment.


METHODS
Young adult CD1 mice (6 to 8 weeks old, male) were used. After anosmic mice were made by bilateral intranasal irrigation with 0.2 ml of 5% (0.17 M) zinc sulfate, anosmia was confirmed by a food finding test. Four groups of anosmic mice were studied: a steroid group (steroid injection group, n=12), an EGb group (EGb injection group, n=12), a steroid-EGb group (steroid and EGb injection group, n=12), and a control group (anosmic mice and no Tx. n=12). The olfactory bulb and piriform cortex of four mice in each group were obtained at 1, 2, and 3 weeks after instillation of zinc sulfate by cardiac perfusion, and immunohistochemical staining for c-fos was also performed to evaluate brain activity. In approximately 10 well-defined glomeruli of the olfactory bulb and in one side of the piriform cortex, c-fos (+) cells were counted. Statistical analyses were performed by Kruskal-Wallis one-way analysis of variance (ANOVA) by rank.


RESULTS
In all experimental groups, c-fos (+) cells increased in a time-dependent manner. The combination treatment of steroid and EGb was the most effective and the no-treatment group the least effective 1 week later after zinc sulfate irrigation. However, 3 weeks later after zinc sulfate irrigation, there was no statistically significant differences in the number of c-fos positive cells among all 4 groups (3 treatment groups and the control group).


CONCLUSIONS
The combination treatment of EGb and steroid enhanced the regeneration of the olfactory pathway after olfactory mucosal injury by zinc sulfate. Our study suggests that EGb could be an effective treatment option for olfactory dysfunction.
Lee
Geun-Suk
GS
Department of Otolaryngology-Head and Neck surgery, College of Medicine, Catholic University of Korea, Seoul, Republic of Korea.
Cho
Jin-Hee
JH
Park
Chan-Soon
CS
Jung
Sang-Hee
SH
Lee
Dong-Hee
DH
Jun
Bum-Cho
BC
Song
Chang-Eun
CE
Cho
Kwang-Jae
KJ
D000818:Animals; D020441:Ginkgo biloba; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D000857:Olfaction Disorders / Q000139:chemically induced / Q000378:metabolism* / Q000628:therapy*; D009831:Olfactory Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects*; D013997:Time Factors; D019287:Zinc Sulfate / Q000008:administration & dosage / Q000009:adverse effects
D016760:Proto-Oncogene Proteins c-fos; D019287:Zinc Sulfate