2012 Fiscal Year Final Research Report
Mouse microRNA expression study identifying the nature of age-related hearing loss
| Project/Area Number |
22591876
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Masatoki 東京医科歯科大学, 医学部附属病院, 助教 (80401355)
ITO Taku 東京医科歯科大学, 大学院・医歯学総合研究科, 助教 (40401400)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 老人性難聴 / 内耳 / 蝸牛 / 加齢 / マイクロ RNA / mRNA / 発現解析 / C57BL/6 |
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| Research Abstract |
MicroRNAs (miRNAs) are approximately 22 nucleotide, double-stranded, non-coding RNAs. They are shown to regulate the stability and translation of the target RNAs, and are associated with many disorders and aging. The aims of the present study are to investigate the time-course changes in miRNA expressions in the cochlea of age-related hearing loss mouse and to clarify the nature of age-related hearing loss.C57BL/6 mouse was used as a mouse model of age-related hearing loss.
Auditory brainstem responses (ABRs) and distortion-product otoacoustic emissions (DPOAEs) were carried out to evaluate the auditory functions. ABR thresholds for tone-burst stimuli at 8, 16, and 32 kHz rapidly increased at 10 months of age, and reached undetectable levels by 16 months of age. DPOAE levels gradually decreased to the noise levels by 12 months of age. Thirty-six ears from 18 mice at the age of 1 month, 36 ears from 18 mice at the age of 10 months, and 30 ears from 15 mice at the age of 16 months were used for miRNAexpression analyses. Membranous labyrinths were dissected from otic capsules in RNAlater solution. Total RNAs including small RNAs were purified by each age group. The quality and quantity of each RNA preparation were determined using a Model 2100 Agilent BioAnalyser. miRCURY LNA microRNA Array (Exiqon) was used for miRNA expression profiles. Non-hierarchical cluster analysis of miRNA expressions detected 42 miRNAs that could be associated with age-related hearing loss.
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