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Objective: To detect the expression of Math1, Hes1 and Hes5 in greater epithelial ridge (GER) cells of rat cochlear and explore their influence on hair cell differentiation., Methods: Postnatal day 0 (P0), day 1 (P1) , day 3 (P3) day 4 (P4) and day 5 (P5) rat cochlear were dissected respectively and then pure GER cells were separated by a combinatorial approach of attachment and mechanical separation. The total RNA of GER cells was extracted by Trizol one step method and the expression of Math1, Hes1 and Hes5 in GER cells was detected with reverse transcription polymerase chain reaction., Results: Math1 was expressed in P0 - P5 rat GER cells and Hes1 was expressed only in PO - P3 rat GER cells, while there was no expression of Hes5 in P0 - P5 rat GER cells., Conclusions: Probably only when the expression of Math1 reaches a certain level can it induce GER cells to differentiate into hair cells. Meanwhile this process might controlled by Hes1 to some extent.

Objective: To analyze the clinical diagnosis of auditory neuropathy by retrospective review of the articles published in Chinese Journals in the past 10 years., Methods: The key word of "auditory neuropathy" was used to search all of the articles published in Chinese Journals by the Chinese Bio-medicine Literature Data Base and Chinese Journal Net from 1995 to 2004. The selected subjects of auditory function examination, diagnosis standards were analyzed, respectively., Results: Forty-two articles were collected, and 23 articles were clinical researches and case reports. There were 573 patients (1146 ears) in all series, and 480 ears (42%) were accords with the standards of diagnosis of auditory neuropathy. Others were accompanied by cochlea, brain stem and peripheral nerve disorders., Conclusion: The clinical manifestation and hearing examination on auditory neuropathy in Chinese journal literatures is inconsistent with the diagnosis standards, moreover, it is necessary to further explore the pathological location and unify the diagnosis standards of auditory neuropathy.

Objective: To determine the protective effects of basic fibroblast growth factor (bFGF) on cochlear neurons and hair cells in vitro and in vivo., Material and Methods: In Experiment I, cultured spiral ganglion neurons (SGNs) prepared from postnatal Day 3 mice were exposed to 20 mM glutamate for 2 h before the culture medium was replaced with fresh medium containing 0, 25, 50 or 100 ng/ml bFGF. Fourteen days later, all cultures were fixed with 4% paraformaldehyde and stained with 1% toluidine blue. The number of surviving SGNs was counted and the length of the neurites of the SGNs was measured. In Experiment II, in vivo studies were carried out with guinea pigs in which bFGF or normal saline was injected intramuscularly to assess possible protective effects of bFGF on cochlear hair cells and to accelerate the recovery of the auditory brainstem response (ABR). The ABRs were measured before, immediately after and 2 and 4 weeks after exposure to noise., Results: Exposure to 20 mM glutamate for 2 h resulted in an inhibition of neurite outgrowth of SGNs and an increase in cell death. Treatment of the cultures with bFGF led to promotion of neurite outgrowth and an increase in the number of surviving SGNs. In Experiment II, significant (p < 0.05) differences in ABR thresholds were observed between the groups injected with bFGF and saline (t = 2.689) at 4 weeks after noise exposure. Cochleae were removed and hair cell loss analyzed in surface preparations prepared from all experimental animals. Acoustic trauma caused loss of 240 and 2160 inner hair cells in the groups injected with bFGF and saline, respectively. Similarly, more outer hair cells were lost in the normal saline injection group (99,291) than in the group treated with bFGF (70,377)., Conclusions: Our results demonstrate that bFGF protects SGNs against glutamate neurotoxicity in vitro. In addition, treatment with bFGF protects hair cells from acoustic trauma.

Objective: In order to assess the reconstructive properties of fascia lata, superficial fascia lata and bone morphogenetic protein (BMP) in skull base surgery, lateral skull base bone and dura mater defect models were established in dogs, Material and Methods: As a repair material we selected fascia lata, either alone or in combination with BMP, for reconstructing large cranial defects in dogs. Twenty dogs undergoing a 3.0 x 4.0 cm2 full-thickness excision of the parietal bone were divided into four equal groups as follows: fascia lata reconstruction; fascia lata reconstruction plus BMP; controls; and fascia lata reconstruction plus BMP with direct exposure of fascia lata. The implants were harvested at 2-15 weeks and examined histologically. Results-Treated and untreated implants were quite different: formation of new bone occurred in the dogs treated with BMP whereas the unreconstructed controls demonstrated only a bridge of fibrovascular connective tissue., Conclusion: The results of this study suggest that it is better to combine BMP and reconstructive material for the treatment of bone defects.

Objective: To construct basic fibroblast growth factor(bFGR) and enhance green fluorescence protein(EGFP) fusion gene eukaryotic expression vector internal ribosome entry site (pIRES)-bFGF-GFP and to evaluate the effect of transduction bFGF gene on noise induced hearing-loss in inner ear hair cells of guinea pigs., Methods: Human bFGF cDNA was inserted into mammalian expressed plasmid pIRES-EGFP. The recombinant expression plasmid pIRES-bFGF-EGFP was transfected into inner ear of guinea pigs, using lipofectin method. The transduced bFGF gene was mediated by SA lipidsome. IRES- bFGF-GFP was administered into the round window as rescue agent at the same time of noise exposure or as a protective agent 7 days before., Results: SA liposome-mediated bFGF expressed at a high level in the cochlea of guinea pigs, and in the rescue group, a significant lower hearing thresholds was displayed. pIRES- bFGF-EGFP could protect hair cells. It demonstrated that pIRES- bFGF-GFP could protect the inner ear both structurally and functionally. bFGF/EGFP gene could be transcripted and translated into inner ear hair cells of guinea pig. bFGF/EGFP gene could express a specific protein. The recombinant bFGF/EGFP had significant protective effect as well as manifestation of autonomous fluorescence., Conclusion: bFGF/EGFP fusion protein not only expressed in hair cells of guinea pig but also showed significant bFGF activity and autonomous fluorescence. IRES induced exogenous gene could enter the hair cells.

Numerous studies have shown that the health of spiral ganglion neurons is highly important for hearing. As a trophic factor of spiral ganglion neurons, neurotrophin 3 (NT3) is a potential candidate for prevention of spiral ganglion neuron degeneration in human. In our experiments, efficient transduction and long term expression of foreign gene of cochlea cells has been found with adenovirus carried lacZ gene (Ad-lacZ). A model of guinea pig deafness was made by intense noise exposure, which destroyed the entire organ of Corti in the middle part of the cochlea. Seven days after noise exposure, the animals were anesthetized and 1 10(8) recombinant adenoviral particles were injected into the scala tympani through the round window membrane. Animals inoculated with neurotrophin 3 adenovirus(Ad-NT3) were designated as the experimental group, animals inoculated with Ad-lacZ vector served as the control group. Four weeks after the inoculation of the virus, NT3 immunoreactivity was observed in the Ad-NT3 inoculated group. HE histochemical staining results showed that in the Ad-lacZ injected group, the neuronal degeneration was severer and the density of spiral ganglion neurons was significantly lower than those in the Ad-NT3 injected group. Our results demonstrate that with adenovirus-mediated overexpression NT3 may be developed into a new treatment to prevent secondary spiral ganglion degeneration following the damage to Corti organ.

The purpose of this study was to observe the protective effects of basic fibroblast growth factor (bFGF) on the cells of the inner ear using in vivo experiments. The studies were carried out using guinea pigs in which bFGF or artificial perilymph was perfused into the cochlea. The compound action potential (CAP) was measured before and after exposure to a sound simulating an explosion. The difference in CAP was significant between the bFGF-perfused group and the control group (p < 0.01, t = 3.896) and between the bFGF-perfused group and the artificial perilymph-perfused group (p < 0.05, t = 2.520). The cochleae were removed and hair cell loss estimated from surface preparations. Acoustic trauma caused loss of outer hair cells in the first and second turns of the cochlea in the bFGF-perfused group and the artificial perilymph-perfused group and partial loss of inner hair cells in the control group. Treatment with bFGF reduced the loss of inner hair cells compared to that of control animals. Our results demonstrate that treatment with bFGF protects the hair cells from acoustic trauma and may facilitate the recovery of hearing.

Forty-one patients of autoimmune inner ear disease were examined with the clinical audiometry and immunocytochemical method. The results showed that there were sensorineural hearing loss in all patients. Serum immunoglobulins (IgG, IgA, IgM) elevation in 14 of 41 patients and antibodies against inner ear tissue in 4 of 41 patients were observed. It suggests that there is specific antibody against inner ear in the serum of patients with autoimmune inner ear disease, and this disease may be originated from the cochlea or the retrocochlea. The method of clinical analyses, the standards of diagnosis and the principles of treatment were discussed.