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Abstract Introduction Vitiligo is an acquired pigmentary disorder of unknown etiology, clinically characterized by whitish macules caused by selective loss of melanocytes. There are many melanocytes in the human cochlea. Recent studies have suggested a direct relation between cochlear dysfunction and decreased amounts of melanin. Objective To determine the effect of vitiligo on auditory function. Methods The present prospective, case control study was performed over a period of 1 year in patients between 15 and 40 years old with nonsegmental disease and the same number of controls. Pure tone audiometry (PTA) and Otoacoustic emission (OAE) were performed to analyze the correlation between vitiligo and auditory function. Results The mean pure tone audiometric threshold in the right ear at 0.5, 8 kHz, and in the left ear at the frequency of 8 kHz in the case group were significantly higher as compared with controls. The average band reproducibility (%) in the right and left ear of controls was significantly higher at the frequency of 4 kHz as compared with cases. It has been observed that signal to noise ratio was statistically higher at the frequency of 5kHz in the right ear and at 2, 3, and 5kHz in the left ear in controls as compared with cases. On the basis of disease type and duration of disease; mean pure tone audiometric threshold, average band reproducibility and signal to noise ratio, no significant effect was observed in the present study. Conclusion Vitiligo has an effect on cochlear function irrespective of the duration or distribution of the disease.
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OBJECTIVE Aimed to observe the changes of acetylated histone H2B in the marginal cells of stria vascularis and spiral ganglion cells from the noise-induced hearing loss model (NIHL). METHODS Fifty guinea pigs were randomly divided into control and noise-exposure group. Auditory brainstem response threshold shift was examined before noise exposure and at 1h after noise exposure (122 dB SPL, 3 h). Immunofluorescence staining and western blot were used to observe the expression of acetyl-histone H2B both in the marginal cells of stria vascularis and spiral ganglion cells of modiolus 2 h after noise expose in two groups. RESULTS There was no significant difference in hearing threshold of 4, 8, 16, 32 kHz for the two groups before noise exposure. The hearing threshold was beyond 90dB (the maximum output) at 4,8,16 and 32 kHz 1h after noise exposure. The expression of acetylated histone H2B significantly decreased with immunofluorescence staining in the marginal cells after noise stimulation. Accordingly, the protein level of acetylated histone H2B in the lateral wall of cochlear decreased obviously in the noise group compared to the control, the ratios of H2B-AcK5/p-actin were 0. 3471 ±0. 0843 and 0. 6114 ±0. 0207 respectively(t=5. 268,P＜0. 01). There was no obvious difference for the expression of acetylated histone H2B in the modiolar tissue between two groups, the ratio of H2B-AcK5/p-actin was 0. 4993 ± 0. 0994 for the noise group and 0. 5139±0. 0132 for the controI (P＞0. 05). CONCLUSION Noise exposure significantly decreased histone acetylation expression in the nuclei of strial marginal cells, whereas the level in the spiral ganglion cells remained stable. Histone acetylation imbalance in the marginal cells of stria vascularis may contributed to the occurrence ofNIHL.
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Objective To investigate the expression of transmembrane protein 16A (TMEM16A)in the cochlea of guinea pigs and its relationship with the age-related hearing loss.Methods We used auditory brainstem response (ABR)to explore the changes of hearing in guinea pigs of different age (groups of 2 w,3 m,1 y,and D-galactose).The distribution and expression of TMEM16A in the cochlea were detected by immunofluorescence and Western blot.Results ABR threshold was gradually increased,with significant difference between D-gal and the other three groups (P <0.01).TMEM16A was expressed in the cochlear striae vascularis at different ages,and the expression increased with age before 1 y (P <0.05). However, its level was increased in D-gal group and significantly differed from that in 3 m and 1 y groups (P < 0.05 ).Conclusion The change in TMEM16A expression in the cochlear striae vascularis of guinea pigs may be related to age-related hearing loss.
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Objective To investigate the expression of transmembrane protein 16A (TMEM16A)in the cochlea of guinea pigs and its relationship with the age-related hearing loss.Methods We used auditory brainstem response (ABR)to explore the changes of hearing in guinea pigs of different age (groups of 2 w,3 m,1 y,and D-galactose).The distribution and expression of TMEM16A in the cochlea were detected by immunofluorescence and Western blot.Results ABR threshold was gradually increased,with significant difference between D-gal and the other three groups (P <0.01).TMEM16A was expressed in the cochlear striae vascularis at different ages,and the expression increased with age before 1 y (P <0.05). However, its level was increased in D-gal group and significantly differed from that in 3 m and 1 y groups (P < 0.05 ).Conclusion The change in TMEM16A expression in the cochlear striae vascularis of guinea pigs may be related to age-related hearing loss.
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Objective To investigate the expression of inducible nitric oxide synthase(iNOS) in the cochlear stria vascularis(SV) of guinea pigs after streptomycin(SM).Methods Auditory brainstem response(ABR) was used as measurement index,and combining with transmission electron microscope(TEM),immunohistochemical staining and image quantitative analysis technique, to detect iNOS expression in the cochlea stria vascularis of guinea pigs and the change of morphology after SM.Results 10 days after adminitration, ABR threshold of SM group increased more significantly than that of the control group(P
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BACKGROUND AND OBJECTIVES: Histones, a set of highly cationic proteins essentially involved in the binding and packing of DNA in the cell nucleus chromatin, have five subclasses (H1, H2a, H2b, H3, H4) in mammalian animals. These components play the most important role in producing autoantibody in SLE and etc. Some studies proposed that there were a relationship between the activity of the disease and the titer of these autoantibody. Recently, histones were revealed to be involved in the immune deposit on GBM in MRL/lpr mice, and cause immune-mediated glomerulonephritis in normal animals. MATERIALS AND METHODS: We examined IgG deposition on the basement membrane of strial capillaries and recorded the endocochlear potential from the basal turn by an electrode inserted though the round window in guinea pigs which was injected by histone(H2a) and anti-histone antisera. RESULTS: IgG depositions were seen on the basement membrane of stria capillaries. IgG was also found to be accumulated on the extravascular side of the basement membrane. However, C3 was almost never observed in the stria vascularis of histone and the anti-histone antisera injected group. In these animals, intracellular edema was evident in the stria vascularis especially at the second and more apical turns but no inflammatory cell infiltration was present. The signifcant decrease in EP was observed just after the injection of anti-histone antisera in the animals receiving an intra-arterial injection of histones. CONCLUSION: This study indicated that cationic antigen could be trapped on the negatively charged basement membrane of strial capillaries, leading to the in situ immune complex formation, and eventually causing immune-mediated hearing loss.
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Animals , Mice , Antigen-Antibody Complex , Basement Membrane , Capillaries , Cell Nucleus , Chromatin , DNA , Ear, Inner , Edema , Electrodes , Glomerulonephritis , Guinea Pigs , Hearing Loss , Histones , Immune Sera , Immunoglobulin G , Injections, Intra-Arterial , Plants , Stria VascularisABSTRACT
BACKGROUND AND OBJECTIVES: The endolymph produced from cochlear lateral wall regulates fluid and maintains positive endocochlear potential. Although many immunohistochemical studies of ion transport enzymes in the cochlear lateral wall have been reported, their mechanisms are still not completely understood. And there are no reports on the studies of anti-Na+ channels in the cochlea of the guinea pig. The voltage-dependent ion channels are fundamental components of neuronal activity. The Na+ channel has a single alpha subunit with 4 pseudosubunits of 6 transmembrane segments each. Expression of the pore-forming and voltage-sensing alpha or alpha1 subunit typically leads to the appearance of channels with voltage- and time-dependent gating and ion conductance. The purpose of this study is to evaluate the expression of the Na+ channel type I and II in the cochlea lateral wall. MATERIALS AND METHODS: We investigated the protein identification by western blot after homogenization and immunohistochemical localization by FITC to the anti-Na+ channel type I and II in the cochlea of the Preyer's positive, white guinea pigs. RESULTS: The results showed that the anti-Na+ channel type I and II were expressed strongly in the intermediate cells of the stria vascularis, and weakly in the stria vascularis. CONCLUSION: We suggest that there are voltage-dependent Na+ channels in the stria vascularis of cochlea and those functions are further evaulated physiologically by the patch clamp technique.
Subject(s)
Animals , Blotting, Western , Cochlea , Endolymph , Fluorescein-5-isothiocyanate , Guinea Pigs , Guinea , Ion Channel Gating , Ion Channels , Ion Transport , Neurons , Stria VascularisABSTRACT
Objective To observe the effect of furosemide on stria vascularis cultivated in vitro from guinea pig, to explore the probable mechanism of furosemide ototoxicity.Methods 20 healthy pigmented guinea pigs was randomly divided into two groups: Furosemide group (n=16), control group (n=4). The stria vascularis explant were cultured for 24 hours using the explant-culture technique. Experimental groups were added into imediately different final concentration of Furosemide (60ug/ml?300ug/ml?600ug/ml?1250ug/ml?2500ug/ml) differently, and continuously cultivated 30 minutes or 90 minutes , then observed structure feature of the cultivated stria vascularis .Results Furosemide group did not show pathological changes such as edema of stria vascularis,shrinkage of the intermediate cells and enlargement of intercellular spaces. No significant changes were found in the stria vascularis structure features between furosemide group and control group. Conclusion Furosemide did not induce remarkable edema on cultivated stria vascularis from guinea pig.These findings suggested that furosemide might induce ototoxicity by indirect mechanism.