Effects of vitamin E on cortical cataractogenesis induced by elevated temperature in intact rat lenses in medium 199
| Autor: | William M. Ross, M.O. Creighton, M. Sanwal, John R. Trevithick, P. Jill Stewart-DeHaan |
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| Rok vydání: | 1981 |
| Předmět: |
Hot Temperature
medicine.medical_treatment Degeneration (medical) Cataract Cellular and Molecular Neuroscience Organ Culture Techniques In vivo Lens Crystalline medicine Membrane fluidity Animals Vitamin E Tocopherol Incubation Chemistry Sensory Systems Culture Media Rats Ophthalmology Crystallography Membrane medicine.anatomical_structure Biophysics Microscopy Electron Scanning Nucleus |
| Zdroj: | Experimental eye research. 32(1) |
| ISSN: | 0014-4835 |
| Popis: | Intact rat lenses incubated in Medium 199 (M199) at 35·5°C maintain their transparency for at least 9 days. When heated to various temperatures for 1 hr to model cataractogenesis by elevated temperatures, followed by 47 hr at 35·5°C, some lenses developed cataractous opacities, depending on the temperature of incubation. At 39°C, slight globular degeneration of fiber cells appeared, localized in the equatorial region, with globules up to 20 μm in diameter, as has been reported for glucose-induced cataracts. At 40°C the globular degeneration was deeper at the equatorial region, towards the nucleus and extending to the anterior and posterior of the lens. At 47 and 50°C, some very large globules were formed (ca. 200 μm diam.) and the globular degeneration was more extensive. However, at higher temperatures (60°C), lenses did not become opaque. They had normal transparency and acuity, perhaps because they had been fixed, by a process similar to histological fixation. The morphological appearance of such lenses examined by scanning electron microscopy (SEM) was normal. α- d -Tocopherol acetate (vitamin E, 2·4 μ m ), when added to lenses before incubation at 41°C, prevented the globular degeneration usually observed at this temperature. The possibility is discussed that the isolated, intact rat lens in M199 may be much more sensitive to elevation in temperature than is the lens in vivo. The fact that the process of heat-induced cataractogenesis is prevented by vitamin E would indicate several routes of further exploration into the mechanism of this process. Some of the possibilities for vitamin E action are: (a) a bulk effect on membranes (for instance, on membrane fluidity), (b) as a scavenger of free radicals, and (c) some other effect on membranes mediated by its lipid solubility and anti-oxidant properties. The fact that cortical cataracts induced in this model system by either glucose or elevated temperature can be prevented by vitamin E ( d -α-tocopherol) may indicate that some step common to both processes is involved in cortical cataractogenesis. |
| Databáze: | OpenAIRE |
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