Effects of age and sex on the expression of estrogen receptor alpha and beta in the mouse inner ear.
CONCLUSIONS
Estrogen receptor (ER) alpha and beta were expressed in the inner ear, and expression decreased with increasing age. ERalpha may alter cochlear and vestibular sensory transduction, and ERbeta may have a neuroprotective function in the inner ear.


OBJECTIVE
Expression of ERalpha and ERbeta in the mouse inner ear and its alterations with sex and aging were analyzed.


METHODS
Male and female CBA/J mice aged 8 weeks and 24 months were used. The localization and the intensity of ERalpha and ERbeta immunoreactivity in the inner ear of young and old mice of both sexes were investigated by immunohistochemistry.


RESULTS
ERalpha and ERbeta were co-expressed in the inner ear, i.e. in the nuclei of stria vascularis, outer and inner hair cells, spiral ganglion cells and vestibular ganglion cells, vestibular dark cells and endolymphatic sac. Strial marginal cells, outer hair cells and type II ganglion cells showed less expression of ERalpha. No gender- or age-related difference was noted in the expression pattern of ERalpha or ERbeta, but fluorescence intensity of ERalpha was stronger in young female mice than in young male mice. In contrast, ERbeta revealed no significant difference. In the old mice, fluorescence intensities of both ERalpha and ERbeta were significantly decreased in both sexes.
Motohashi
Ray
R
Department of Otolaryngology, Tokyo Medical University, Tokyo 160-0023, Japan. ray-a@td6.so-net.ne.jp
Takumida
Masaya
M
Shimizu
Akira
A
Konomi
Ujimoto
U
Fujita
Koji
K
Hirakawa
Katsuhiro
K
Suzuki
Mamoru
M
Anniko
Matti
M
D000367:Age Factors; D000375:Aging / Q000502:physiology*; D000818:Animals; D001284:Atrophy / Q000378:metabolism / Q000473:pathology; D007758:Ear, Inner / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D004712:Endolymphatic Sac / Q000166:cytology / Q000378:metabolism; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D005260:Female; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism / Q000473:pathology; D018072:Hair Cells, Auditory, Outer / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D008856:Microscopy, Fluorescence; D009925:Organ of Corti / Q000378:metabolism / Q000473:pathology; D012737:Sex Factors; D013136:Spiral Ganglion / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D013316:Stria Vascularis / Q000166:cytology / Q000378:metabolism / Q000473:pathology
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta