title: Acoustical stimulus changes the expression of stromal cell-derived factor-1 in the spiral ganglion neurons of the rat cochlea.
abstract: Neural stem cell (NSC) transplantation into the cochlea has been tested as a treatment for spiral ganglion neuron (SGN) degenerative disease and injury in various animal models. A recent study has shown evidence of functional recovery after transplantation of the stem cells into a degenerated-SGN model. Chemokine stromal cell-derived factor-1 (SDF-1, or known as CXC chemokine ligand-12, CXCL-12) signaling through CXCR4 has previously been identified as a key step in the homing of the stem cells within the injury areas; meanwhile, studies have revealed that the SDF-1/CXCR4 axis is also involved in axon guidance and pathfinding. A study found that transplanted neural precursor cells can migrate to the root of the auditory nerve when animals are subjected to an augmented acoustic environment (AAE). In accordance with these studies, we hypothesize that AAE will up-regulate the expression of SDF-1 in acoustic nerves. We tested our hypothesis by examining the expression of SDF-1 in different acoustic environments, and the results were confirmed by the auditory brainstem response (ABR), immunohistochemical and RT-PCR analyses. The results showed that SDF-1 was expressed at a relatively low level in the SGNs under normal animal unit acoustic conditions (40-50 dB). Moreover, it was significantly up-regulated in the SGNs under the 75 dB (augmented physiological process without hearing loss) and 90 dB AAE (pathological process with light hearing loss) conditions; however, under the 115 dB AAE (pathological process with severe hearing loss) condition, the expression of SDF-1 was not up-regulated. The results confirmed that appropriately augmented acoustical stimuli lead to the up-regulation of SDF-1, which may assist in the migration of the transplanted cells and the subsequent establishment of essential synaptic contacts between the exogenous cells and the host auditory pathway.
authors.affiliation: Ji-Guan Hospital, Lanzhou Military Region, Air Force, PLA, Lanzhou 730020, China; Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Peng-zhi
authors.initials: PZ
authors.lastname: Zhang
authors.affiliation: Department of Aerospace Biodynamics, Faculty of Aerospace Medicine, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Xin-sheng
authors.initials: XS
authors.lastname: Cao
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Xing-wang
authors.initials: XW
authors.lastname: Jiang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Peng-fei
authors.initials: PF
authors.lastname: Liang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Shu-juan
authors.initials: SJ
authors.lastname: Wang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Wen-juan
authors.initials: WJ
authors.lastname: Mi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Fu-quan
authors.initials: FQ
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xue
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. Electronic address: qiujh@fmmu.edu.cn.
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Qiu
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism*; D016057:Evoked Potentials, Auditory, Brain Stem; D034381:Hearing Loss / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009622:Noise; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D013136:Spiral Ganglion / Q000166:cytology / Q000378:metabolism*
chemical_list: D054377:Chemokine CXCL12; D012333:RNA, Messenger
keywords: Augmented acoustic environment; Cochlea; Spiral ganglion neuron; Stromal cell-derived factor-1