High-dose mode of mortality in Tribolium: A model system for study of radiation injury and repair in non-proliferative tissues
With appropriate doses of ionizing radiation, both the acute, or lethal-midlethal, dose-independent pattern of mortality, and the hyperacute, dose-dependent pattern, were demonstrated within a single insect genus (Tribolium). This demonstration provides resolution of apparently contradictory reports of insect radiation responses in terms of doses required to cause lethality and those based on survival time as a function of dose. A dose-dependent mortality pattern was elicited in adult Tribolium receiving high doses, viz., 300 Gy or greater; its time course was complete in 10 days, before the dose-independent pattern of mortality began. Visual observations of heavily-irradiated Tribolium suggested neural and/or neuromuscular damage, as had been previously proposed by others for lethally-irradiated wasps, flies, and mosquitoes. Results of experiments using fractionated high doses supported the suggestion that the hyperacute or high-dose mode of death is the result of damage to nonproliferative tissues. Relative resistance of a strain to the hyperacute or high-dose mode of death was not correlated with resistance to the midlethal mode, which is believed to be the result of damage to the proliferative cells of the midgut. Using the high-dose mode of death as a model of radiation damage to nonproliferative tissues, the effects of age, and of a moderate priming dose were assessed. Beetles showed age-related increase in sensitivity to the high-dose mode of death, suggesting a decline in capacity to repair radiation damage to postmitotic tissue. This correlated with a decrease (50%) in the amount of repair reflected in the sparing effect of dose-fractionation (SDF) between the age of 1 to 3 months. The age related increase in radiosensitivity was reduced by a moderate priming dose (40 or 65 Gy) given at a young age.
- Research Organization:
- Illinois Univ., Urbana, IL (USA)
- OSTI ID:
- 5732822
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
INSECTS
BIOLOGICAL RADIATION EFFECTS
AGE DEPENDENCE
BIOLOGICAL MODELS
BIOLOGICAL REPAIR
DOSE-RESPONSE RELATIONSHIPS
FRACTIONATED IRRADIATION
IONIZING RADIATIONS
MORTALITY
RADIATION DOSES
RADIATION INJURIES
ANIMALS
ARTHROPODS
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
DOSES
INJURIES
INVERTEBRATES
IRRADIATION
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
560152* - Radiation Effects on Animals- Animals