Scanning Electron Microscopy of X-Ray-Induced Cataract in Mice on Normal and Galactose Diet

Kodama, Takao; Reddy, Venkat N.; Giblin, Frank J.; Kinoshita, Jin H.

doi:10.1159/000265280

Cited by 12 publications

(3 citation statements)

References 8 publications

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“…Animals with galactose-induced diabetes [19,20] and streptozotocin-induced diabetes [5] have been studied as models for diabetic cataract and diabetic retinopathy. However, the onset of diabetes in these models is rapid and their life span is very short.…”

Section: Discussionmentioning

confidence: 99%

Lens and Retinal Changes in the WBN/Kob Rat (Spontaneously Diabetic Strain)

Miyamura

Amemiya²

1998

Ophthalmic Res

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Male WBN/Kob rats represent a spontaneously diabetic strain with hyperglycemia, cataracts, nephropathy, neurophathy, pancreatic fibrosis and hyperlipemia. Cataracts and retinal changes in WBN/Kob rats were examined by light and electron microscopy to evaluate the ocular complications. Lens opacity was present in the posterior subcapsular and center of the anterior cortex of male 14-month-old WBN/Kob rats. Light and transmission electron microscopy showed swelling and irregularity of lens fibers. Scanning electron microscopy revealed that lens fibers were irregular and had many granules and bulging processes of various sizes on the cortical side of the opacified region. The nuclear side of the opacified region showed spongy changes and complete absence of lens fibers. Electron microscopy showed retinal degeneration in the photoreceptor outer segments of 1-month-old male WBN/Kob rats. Light microscopy showed thin outer segments and outer nuclear layers in 5-month-old rats, and electron microscopy revealed severe degeneration in the outer segments. The retinas of 11-month-old rats were thinner; the outer plexiform layer was very thin; the photoreceptor cell nuclei in the outer nuclear layer had decreased to one layer and were almost in contact with the inner nuclear layer nuclei, while the visual cells had disappeared. Retinal degeneration had progressed even further in 14-month-old rats, and very few photoreceptor cell nuclei remained. The retinal capillary lumens were small, and their pericytes had thickened basement membranes. The basement membranes of retinal capillaries from WBN/Kob rats were significantly thicker than those from control Wistar rats (p < 0.0001). Although this rat has spontaneous diabetic features, such as cataracts, its retinal changes look more degenerative.

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Section: Discussionmentioning

confidence: 99%

Lens and Retinal Changes in the WBN/Kob Rat (Spontaneously Diabetic Strain)

Miyamura

Amemiya²

1998

Ophthalmic Res

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“…(612) A high galactose diet (30%) reduced radiation-induced lens damage in mice, evaluated by light and electron microscopy (vacuole formation, fibre cell swelling, and morphological disorganisation) (Kodama et al, 1983). These observations were confirmed by slit-lamp examination of irradiated mice lenses for up to 4 months (Taura et al, 1985).…”

Section: Sugarsmentioning

confidence: 93%

ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

Stewart¹,

Akleyev²,

et al. 2012

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This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

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“…The treatment of radiation retinopathy also remains limited and is a serious challenge for modern medicine. Photodynamic therapy, laser photocoagulation, oral pentoxifylline, intravitreal steroid therapy, and hyperbaric oxygen have inconclusive results and limited efficacy [99][100][101][102][103][104][105][106][107][108][109][110][111][112]. Anti-vascular endothelial growth factor agents (anti-VEGF agents) reduce vascular permeability and inhibit the formation of abnormal new vessels.…”

Section: Prevention and Treatmentmentioning

confidence: 99%

Radiation-induced eye impairments

Hristov

2024

IJCCR

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The problem of the impact of ionizing radiation on eye structures is one of the most important and topical in radiobiology. Knowledge of tissue radiosensitivity and induced tissue changes in the eye is essential for understanding the nature of radiation damage and the behavior of medical professionals. In this publication, the early and late determined radiation-induced impairments of the eye are presented as a result of radiotherapy or radiation incidents. The risk factors determining post-irradiation eye reactions, pathophysiological mechanisms, clinical picture, diagnosis, prevention, and new approaches in therapy are presented. We found that the typically found radiation-induced eye impairments are those of the eyelids – dermatosis and madarosis, conjunctiva – acute conjunctivitis, varied damage to the lacrimal apparatus, cornea – edema and ulceration, iris – rarely inflammation or neovascularization, sclera – rarely atrophy or necrosis, eye lens – cataract, retina – characteristic retinopathy, and optical nerve – rarely neuropathy. We provide the current consensus on prevention and treatment protocols in radiation-induced eye impairments, though most suggested treatment so far should qualify as experimental.

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Scanning Electron Microscopy of X-Ray-Induced Cataract in Mice on Normal and Galactose Diet

Cited by 12 publications

References 8 publications

Lens and Retinal Changes in the WBN/Kob Rat (Spontaneously Diabetic Strain)

Lens and Retinal Changes in the WBN/Kob Rat (Spontaneously Diabetic Strain)

ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

Radiation-induced eye impairments

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