Yang Shiming

Effects of Moderate Noise Exposure on Hearing Function in C57BL/6J Mice

Abstract Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly selected to be studied immediately after exposure (Group P0), or 1 day (Group P1), 3 days (Group P3), 7 days (Group P7) or 14 days (P14) after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point. Results ABR threshold elevation was seen at every tested frequency at P0 (P 0.05). Conclusion There is a frequency specific response to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.

Isolation and Induction of Differentiation of Seine Adipose-Derived Mesenchymal Stem Cells

Abstract Objectives To establish a method for high yield mesenchymal stem cells collection, as well as a culture method for identifying mesenchymal stem cells from the swine adipose-derived mesenchymal stem cell (ADMSC). Methods Swine ADMSCs were isolated from fat tissue with collagenase, followed by induction of differentiation to osteogenic, adipogenic and chondrogrnic cells. The survival curve of the ADMSC at the 37°C and 38°C were measured using WST-1Cell Proliferation Assay Reagent. Result ADMSCs isolated with collagenase from swine neck fat tissue generated a stable uniform appearance after the second generation. The passage period was five days. ADMSC could differentiate into osteogenic, adipogenic or chondrogrnic cells under different culture conditions. The highest growth rate was achieved at 38°C in this study. Conclusion Swine ADMSCs have the potential to differentiate into osteogenic, adipogenic or chondrogrnic cells, and they may be appropriate for transplantation for both research and clinical purpose.

COMBINATIONAL ADMINISTRATION OF AMINOGLYCOSIDES AND LOOP DIURETICS AS AN EFFICIENT STRATEGY TO ESTABLISH DEAFNESS MODELS IN RATS

Abstract It is known that aminoglycoside antibiotics can damage the vestibular and auditory sensory epithelia, and the loop diuretics can enhance the ototoxic effect of aminoglycosides. Previous studies on the synergistic effect of these two types of drugs have used mice, guinea pigs and cats, but not rats. The aim of this study was to determine this synergistic effects in rat cochleae. Rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. Auditory brainstem response (ABR), scanning electron microscopy (SEM) and immunocytochemistry were used to determine the effects of drug administration. In the group receiving combined administration of furosemide and kanamycin, the ABR threshold showed significant elevation 3 days after drug administration, greater than single drug administration. The hair cells showed various degrees of injury from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. Neuron fibers of the hair cells showed significant loss 7 days after the drug administration, but the number of spiral ganglia did not decrease and supporting cells showed no signs of injury. Our study suggest that combined administration of furosemide and kanamycin has an synergistic ototoxic effect, and can result in hair cell loss and hearing loss in rats.

MICRODISSECTION OF MINIATURE PIG EAR

Abstract Objective To investigate the suitability of miniature pigs as an animal model for otological research. Methods Microdissection of the temporal bone was performed on 10 miniature pigs and recorded on photographs. Results The morphology and measurement of the external, middle and inner ear and the lateral recess of the miniature pigs were obtained by microdissection. Conclusion Compared to traditional animal models, the miniature pig may be a better model for biomedical research because of its many similarities in physiological functions with humans. Similarities of the temporal bone structures, including the external, middle and inner ear and the lateral recess, between the miniature pig and human make the animal a potentially useful model for otological research.

Diagnosis and Treatment of Auditory Neuropathy and Related Research

Introduction Deafness is one of the most common otologic diseases and a major disease that greatly impacts the Chinese population. From the Second National Sample Survey of Disabled Persons, it is estimated that there are 27,800,000 hearing disabled persons in China, about 2.14% of

The Treatment and Reconstruction of Lateral Skull Base Lesions

Yi Haijin1 and Yang Shiming2* 1Department of Otolaryngology, Head & Neck Surgery, Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing, PR China 2Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing, PR China *Corresponding author: Yang Shiming, Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing, PR China, Tel: +86 10 6821 1696; E-mail: yangsm301@263.net

A Method for Establishing an Animal Model of Like-Auditary Neuropathy

Abstract Objective: To establish an animal model of like-auditory neuropathy in neonatal rat. Methods The animals were injected with phenylhydrazine hydrochloride or saline at 7-day of age. ABR and DPOAE were performed to assess the auditory function. The cochlea basilar membrane stretched preparation and cochlear frozen sections were prepared for immunohistochemical staining to examine the morphological change of hair cells and spiral ganglion cells (SGNs). Results At 7-day age the ABR waveI, III, V, latencies andI- III,I-V IWIs in the experimental group were significantly prolonged compared with those in the control group. The ABR thresholds were also elevated in the experimental group. We found there is no significant difference in DPOAE in phenylhydrazine hydrochloride exposure group compare to control group. The cochlear hair cells showed no signs of loss in both group, but the total number of neurofilaments positive cells in SGNs were significantly reduced in the phenylhydrazine treated animals. Conclusion Our study suggests that phenylhydrazine hydrochloride can change the auditory function and induce peripheral nerve pathology by targeted mainly the SGNs in neonatal rat.

Lower Dose of Aminoglycoside Ototoxic Exposure Causes Presynaptic Alterations Assoicated with Hearing Loss

Abstract Objective To study presynaptic alternations of cochlear ribbons arising from aminoglycoside ototoxic stimuli in C57BL/6J mice. Methods Animals were injected with low dose gentamicin (100 mg/kg/day) for 14 days, From the 14th to 28th days, the mice were maintained free of gentamicin treatment. Immunohistochemistry labeling was employed to trace RIBEYE, a major presynaptic componment of ribbon synapses. RIBEYE/CtBP2 expression levels were assessed and compared with hearing threshold shifts. Auditory function was assessed by auditory brainstem responses. The stereocilia of outer hair cells (OHCs) and IHCs was examined by scanning electron microscopy (SEM). Results Hearing thresholds were elevated with peak hearing loss observed on the 7th day after gentamicin exposure, followed by improvement after the 7th day. RIBEYE/CtBP2 expression directly correlated with observed hearing threshold shifts. Strikingly, we did not see any obvious changes in stereocilia in both OHCs and IHCs until the 28th day. Mild changes in stereocilia were only observed in OHCs on the 28th day. Conclusions These findings indicate that presynapse cochlear ribbons, rather than stereocilia, may be sensitive to aminoglycoside ototoxic exposure in mice cochleae. A pattern of RIBEYE/CtBP2 expression changes seems to parallel hearing threshold shifts and suggests presynaptic response properties to lower dosage of aminoglycoside ototoxic stimuli.

The Cochlear Ribbon Synaptic Response to Aminogiycoside Ototoxicity in C57BL/6J Mice

Abstract Objective To investigate the early change of cochlear ribbon synapses on inner hair cells in response to aminoglycoside ototoxicity. Methods C57BL/6J mice received intraperitoneal injection of gentamicin (100 mg/kg/day), and the apical coil organ of Corti was examined on the 4th, 7th and 10th day (n=10). Littermates without gentamicin treatment served as controls (n=10). RIBEYE on the presynaptic membrane and AMPA receptors on the postsynaptic membrane were labeled with CtBP2 or GluR2/3 respectively. Three dimension reconstruction was conducted using the 3DS MAX 8.0 software. Results There were no disruptions of outer or inner hair cells in all groups. However, the number of ribbon synapses on cochlear inner hair cells increased significantly within 7 days after gentamicin exposure (P Conclusion During the early stage of aminoglycoside ototoxicity, increased population of cochlear ribbon synapses may indicate a significant down-regulation of synaptic function.

Utility of Vibrant Soundbridge in Patients with Congenital Middle and Outer Ear Deformities

Abstract Objective To report use of the Vibrant Soundbridge (VSB) in patients with congenital deformation of the middle and outer ears and investigate its utility in this patient population. Method Four patients with congenital deformation of middle and outer ears underwent VSB implantation. All were male (aged 3-18 years, average 13.5 years) and operated on the left side. Malformation was bilateral in 3 patients and unilateral in 1 patient. Surgical techniques were modified to accommodate each patients unique conditions and needs. The implant site was approached via the facial recess in 3 patients and through a retro-facial nerve route in 1 patient. The VSB implant was connected to either the stapes (2 cases) or the round window (2 cases). Pure tone and speech audiometry results and daily communication capabilities before and after VSB activation were compared. Results The operations were successful in all patients, with no complications. The patient communication level improved significantly after VSB activation. Average air conduction pure tone threshold or conditioned reflex audiometry threshold improved by 35 dB in the 0.25-4 kHz range, from 69 dB HL before VSB activation to 34 dB HL after. The sentence recognition rate in quiet at 65 dB SPL went up to 86% from 0% without VSB for patients with bilateral deformation and remained at 100% for the patient with unilateral deformity. However, for the latter patient, the rate improved to 20% from 0% without VSB in noise (-8 dB SNR). Conclusion VSB is an excellent solution for improving hearing in patients with congenital deformation of middle and outer ears. Operation can be completed and good results can be achieved even in patients with unique conditions and needs.