Photochemically induced focal cochlear lesions in the guinea pig: II. A transmission electron microscope study

Miyashita, Hiroshi; Iwasaki, Satoshi; Hoshino, Tomoyuki

doi:10.1002/(sici)1097-0029(19980515)41:4<334::aid-jemt6>3.0.co;2-q

Cited by 7 publications

(3 citation statements)

References 9 publications

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“…Our SEM observations also showed that degeneration of the OHC occurred far later than that of the strial marginal cells. Transmission electron microscope observations by Miyashita et al [14] demonstrated that when both the lateral wall and organ of Corti were illuminated vertically, strial marginal cell degeneration occurred at 20 min after RB infusion and illumination but OHC degeneration was seen 12 h after photochemical treatment. Even in the severest strial damage seen by us, the OHC did not completely disappear but cells remained sporadically.…”

Section: Discussionmentioning

confidence: 99%

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A new model for investigating hair cell degeneration in the guinea pig following damage of the stria vascularis using a photochemical reaction

Ocho

Iwasaki

Umemura

et al. 2000

European Archives of Oto-Rhino-Laryngology

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We have established a new model for investigating the relationship between cochlear lateral wall damage and sensory cell degeneration in guinea pigs by using a photochemical reaction between the systemic injection of Rose Bengal (RB) and controlled green light irradiation to the cochlea. The photochemical reaction produced a reactive oxygen species, which then damaged the endothelium. This triggered platelet adhesion and aggregation at the site of endothelial injury to produce thrombi and affect microcirculation in the lateral wall at the site of irradiation. Changes were studied under a scanning electron microscope (SEM), and compound action potentials (CAP) were measured. SEM observations after tangential illumination of the cochlear wall revealed degeneration of the stria vascularis (SV). Specific morphological findings at 24 h included delayed degeneration of the outer hair cells concurrent with a significant increase in the CAP. Based on these findings, we suggest that degeneration of the SV was a direct result of the photochemical reaction, but CAP changes and sensory hair cell damage were secondarily caused by SV degeneration.

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Section: Discussionmentioning

confidence: 99%

“…We have already established a different model for inner ear microcirculatory disorders [7,9,14,23,24]. Vertical illumination in that model shed both the lateral wall and the organ of Corti, so that the inner and outer hair cells might have been exposed to the direct influence of the photochemical reaction.…”

Section: Introductionmentioning

confidence: 99%

A new model for investigating hair cell degeneration in the guinea pig following damage of the stria vascularis using a photochemical reaction

Ocho

Iwasaki

Umemura

et al. 2000

European Archives of Oto-Rhino-Laryngology

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“…It has been proposed that damage to the marginal cells of the stria vascularis secondarily causes damage to the OHC [22,23]. In a study by Miyasha et al, photochemically induced damage to the cochlea with Rose Bengal dye and green light irradiation resulted in marginal cell extrusion and rupture, followed by OHC damage 12 or more hours after strial insult as seen by TEM.…”

Section: Pathophysiology Of Cisplatin Ototoxicity: Early Damage To Thmentioning

confidence: 98%

Recovery from cisplatin-induced ototoxicity: A case report and review

Truong¹,

Winzelberg²,

Chang³

2007

International Journal of Pediatric Otorhinolaryngology

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Effects of corticosteroid, contrast medium and ATP on focal microcirculatory disorders of the cochlea

Nagura

Iwasaki

et al. 1999

European Journal of Pharmacology

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We evaluated the ability of various drugs to prevent the decrease in focal cochlear blood flow induced by photochemical reaction and investigated the mechanisms underlying this decrease. By means of a photochemical reaction, which produces reactive oxygen species, focal lesions measuring about 1 mm in diameter were induced in the lateral wall of the guinea pig cochlea. The protective effects of hydrocortisone, amidotrizoate and ATP on cochlear blood flow and cochlear vascular conductance changes were evaluated by using a non-contact laser flowmeter. Cochlear blood flow and cochlear vascular conductance were decreased to 65.1+/-4.9% (mean +/- S.E.M.) and 57.0+/-3.7% (mean +/- S.E.M.) of the initial level 30 min after the start of the photochemical reaction, respectively. Hydrocortisone significantly prevented the decline in the cochlear blood flow and cochlear vascular conductance and reduced the area of stria vascularis degeneration in a dose-dependent manner. Neither amidotrizoate nor ATP significantly prevented the decrease in cochlear blood flow or cochlear vascular conductance. Hydrocortisone was more effective than vasodilators or other agents which increase cochlear blood flow in preventing the photochemically induced decrease in cochlear blood flow. This might be due to the antioxidative effects of hydrocortisone.

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Photochemically induced focal cochlear lesions in the guinea pig: II. A transmission electron microscope study

Cited by 7 publications

References 9 publications

A new model for investigating hair cell degeneration in the guinea pig following damage of the stria vascularis using a photochemical reaction

A new model for investigating hair cell degeneration in the guinea pig following damage of the stria vascularis using a photochemical reaction

Recovery from cisplatin-induced ototoxicity: A case report and review

Effects of corticosteroid, contrast medium and ATP on focal microcirculatory disorders of the cochlea

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