Abstract | PURPOSE: To investigate the mechanism and sequence of formation of ring-shaped mitochondria in retinal pigment epithelial cells of a chick model of gyrate atrophy. METHODS: Electron microscopic analysis of the ultrastructure of retinal pigment epithelial (RPE) mitochondria was carried out in chicks injected intravitreally with formoguanamine regularly (every 4 days) over the first 2 weeks or 4 weeks post-hatching. Formoguanamine is a triazine drug which induces hyperornithinemic symptoms in the chick eye similar to those seen in human gyrate atrophy. RESULTS: A large population of irregularly shaped mitochondria was observed in the RPE of both peripheral and central retina. They showed extensive morphological changes. At 2 wk, the mitochondria appeared enlarged and abnormal in shape with vacuolisation, partial loss of their double membrane and reduced mitochondrial cristae. By 4 wk, the mitochondria had assumed a rounder, almost circular profile, many with central holes, so-called ring mitochondria. CONCLUSION: The appearance of ring-shaped mitochondria has been previously ascribed to the section of cupshaped three-dimensional structures. We present evidence that ring-shaped mitochondrial profiles arise through at least two different mechanisms of membrane breakdown and intraorganelle vacuolisation. The nature of the three dimensional structures of these abnormal mitochondria is re-examined.
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Authors | H Liang, S G Crewther, D P Crewther |
Journal | Yan ke xue bao = Eye science
(Yan Ke Xue Bao)
Vol. 11
Issue 1
Pg. 9-15
(Mar 1995)
ISSN: 1000-4432 [Print] China |
PMID | 8575612
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
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Topics |
- Animals
- Chick Embryo
- Disease Models, Animal
- Gyrate Atrophy
(chemically induced, pathology)
- Mitochondria
(ultrastructure)
- Pigment Epithelium of Eye
(ultrastructure)
- Triazines
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