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Article in English | WPRIM | ID: wpr-652968


BACKGROUND AND OBJECTIVES: Endolymphatic hydrops has been considered as an important histologic substrate of Meniere's disease. A permanent displacement of basilar membrane (BM) by increased endolymphatic pressure has been thought to be an explanation for hearing change. Direct observation of histological sections of temporal bones, however, suggested that stereocilia and tectorial membrane decoupling is more associated with pressure induced by mechanical deformation of the organ of Corti rather than with the displacement of BM. METERIALS AND METHOD: 26 cochleae from 13 female pigmented ginea pigs were harvested. One cochlea per each animal was injected with artificial perilymph. The other one was used as control. After fixation, followed by embedding and mid-modiolar sectionning, specimens were observed with a microscope. Morphometric parameters of each row and turn of the organ of Corti were measured and quantified. RESULTS: The average area and height of the organ of Corti were significantly smaller in the apical turn of the experimental group (p<0.05). The lengths of outer hair cell and Deiters cell in the apical turn were also significantly reduced in the experimental group (p<0.05). The angle between the outer hair cell and Deiters cell was smaller in the apex and in the 3rd turn of the experimental group (p<0.05). CONCLUSION: Results show that compression and deformation of the organ of Corti, especially in the apical turn, is a prominent feature in the acute endolymphatic hydrops model. We suggest that the deformation of organ of Corti is the primary cause of hydrops that induce the decoupling of tectorial membrane and stereocilia rather than the displacement of BM.

Animals , Basilar Membrane , Cochlea , Edema , Endolymphatic Hydrops , Female , Guinea Pigs , Hair , Hearing , Humans , Meniere Disease , Organ of Corti , Perilymph , Stereocilia , Swine , Tectorial Membrane , Temporal Bone
Article in Chinese | WPRIM | ID: wpr-406501


Objective To investigate the cellular localization of the neural precursor cell-expressed, developmentally downregulated isoforms(Nedd4), Nedd4- 1/2 and Nedd4- 2, and the serum glucocorticoid- inducible kinasel(SGK1) in various subregions of the rat cochlea. Methods The expression patterns of Nedd4-1/2, Nedd42 and SGK1 in the cochlea of rat were studied by immunohistochemistry with the specific polyclonal rabbit antibodies against the rat Nedd4-1/2, Nedd4-2 and SGK1. Results All three proteins were extensively expressed in various regions of the rat cochlea. They were found in the stria vascularis, spiral ligament, organ of Corti, spiral limbus, spiral ganglion and Reissner's membrane. Conclusion Our findings suggest that there exists a Na+ transport system in the cochlea consisting of SGK1, Nedd4 isoforms and ENaC, which may work in concert to transport Na+ and to maintain homeostasis in the inner ear as they do in other tight epithelia.

Article in Chinese | WPRIM | ID: wpr-525609


Objective To create a method to assay adriamycin in endolymph of guinea pig cochlea,and provide methodology background to study the accumulation of ototoxicity substance in inner ear.Methods 12 normal guinea pig were killed quickly after 24 hours following adriamycin injection.The concentrate of adriamycin in endolymph of guinea pig cochlea was assayed by high performance liquid chromatography(HPLC).Results The linear relation of concentration of adriamycin in endolymph was well when the concentration was from 2.56 ng/mL to 1398.00 ng/mL.Correlation coefficient of linearity was 0.999 (n=10).The percentage of retrieve for adriamycin in endolymph was 96.3%.Relative standard deviation (RSD) was 2.61%.The lowest limitation was 1.9 ng/ml .Conclusion The sensibility of HPLC is high,and it can accurately detect the concentration of adriamycin in endolymph of guinea pig cochlea,especially the adriamycin is administrated in vein.

Article in Korean | WPRIM | ID: wpr-654863


The endolymphatic secretory epithelium are stria vascularis in cochlear and dark cell in vestibule which are regulated by Na+-K+ ATPase. It is important that we study intracytoplasmic Na+-K+ ATPase for the physiologic research of inner ear. Recently cerium-based method for stain of Na+-K+ ATPase was developed. This study was underkaken to investigate the morphologic changes and Na+-K+ ATPase activity in stria vascularis and vestibular dark cell of mongolian gerbil after systemic intramuscular injection(200mg/kg or 300mg/kg) for 7days or local infiltration of streptomycin through round window. The results are as follows. 1) The strong Na+-K+ ATPase activity was seen at basolateral infoldings of marginal cell in stria vascularis but weak Na+-K+ ATPase activity in dark cell near transitional area. 2) There was no change of Na+-K+ ATPase activity in the stria vascularis and dark cell by systemic injection of streptomycin. The decrease of Na+-K+ ATPase activity in stria vascularis was seen at destruction site of infoldings by local infiltration of streptomycin but no changes in dark cell. 3) The ultrastructural changes of marginal cell by local infiltration of streptomycin were intracytoplasmic vacuole, partial loss of cytoplasmic infoldings, edema, and increase of melanin particle. but, there was no change of ultrastructure in dark cell except increase of melanin particle. The changes of ultrastructure of stria vascularis was variable by systemic streptomycin injection and there was no dark cell change except increased melanin particle. From the above results, the changes of ultrastructure and Na+-K+ ATPase were more severe by local infiltration of streptomycin through round window than systemic injection of streptomycin. The local infiltration of streptomycin through round window may be suitable method for the induction of inner ear damage.

Adenosine Triphosphatases , Cytoplasm , Ear, Inner , Edema , Epithelium , Gerbillinae , Melanins , Streptomycin , Stria Vascularis , Vacuoles