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Alteration of strial capillary transport in kanamycin-treated guinea pigs
Abstract:
Ferritin transport through the strial capillary during kanamycin intoxication was examined under a transmission electron microscope. Twelve guinea pigs were treated intramuscularly with kanamycin (400 mg/kg/day) for 2-3 weeks. When full hearing loss was recognized by estimating the Preyer reflex or auditory brain-stem response (ABR), ferritin was given intravenously and animals were sacrificed 1/3, 1, and 2 h later. At 1/3 h, ferritin was present diffusely not only in the endothelial cell but also in the basal lamina and within vesicles in the strial cell. Alternatively, it was discharged into the endolymphatic space. At 2 h, ferritin was seen on the luminal surface and in the cytoplasm of the endolymphatic cells of Reissner's membrane. These results suggest that the basal lamina of the strial capillary was altered qualitatively by kanamycin administration.
Insights
Kanamycin damages the inner ear by altering strial capillary basal lamina, affecting ferritin transport and potentially causing hearing loss. This study reveals key changes in ferritin
Area of Science:
- Ototoxicity research
- Inner ear physiology
- Electron microscopy
Background:
- Kanamycin is an ototoxic antibiotic known to cause hearing loss.
- The stria vascularis plays a crucial role in maintaining the endolymphatic environment essential for hearing.
Purpose of the Study:
- To investigate the effect of kanamycin intoxication on ferritin transport across the strial capillary.
- To elucidate the structural changes in the strial capillary basal lamina induced by kanamycin.
Main Methods:
- Transmission electron microscopy was used to examine ferritin transport in guinea pigs.
- Animals received kanamycin and intravenous ferritin at different time points post-intoxication.
Main Results:
- Ferritin was observed within endothelial cells, basal lamina, and strial cells within 1/3 hour after administration.
- Ferritin was also found in the endolymphatic space and on Reissner's membrane cells at later time points.
- Kanamycin administration altered the strial capillary basal lamina, facilitating ferritin passage.
Conclusions:
- Kanamycin-induced ototoxicity involves qualitative alterations of the strial capillary basal lamina.
- These changes impact the transport of molecules like ferritin, potentially contributing to hearing loss.