Abstract
BackgroundElevated levels of environmental ionizing radiation can be a selective pressure for wildlife by producing reactive oxygen species and DNA damage. However, the underlying molecular mechanisms that are affected are not known.ResultsWe isolated skin fibroblasts from bank voles (Myodes glareolus) inhabiting the Chernobyl nuclear power plant accident site where background radiation levels are about 100 times greater than in uncontaminated areas. After a 10 Gy dose of gamma radiation fibroblasts from Chernobyl animals recovered faster than fibroblasts isolated from bank voles living in uncontaminated control area. The Chernobyl fibroblasts were able to sustain significantly higher doses of an oxidant and they had, on average, a higher total antioxidant capacity than the control fibroblasts. Furthermore, the Chernobyl fibroblasts were also significantly more resistant than the control fibroblasts to continuous exposure to three DNA damaging drugs. After drug treatment transcription of p53-target gene pro-apoptotic Bax was higher in the control than in the Chernobyl fibroblasts.ConclusionFibroblasts isolated from bank voles inhabiting Chernobyl nuclear power plant accident site show elevated antioxidant levels, lower sensitivity to apoptosis, and increased resistance against oxidative and DNA stresses. These cellular qualities may help bank voles inhabiting Chernobyl to cope with environmental radioactivity.
Highlights
Elevated levels of environmental ionizing radiation can be a selective pressure for wildlife by producing reactive oxygen species and DNA damage
Chernobyl fibroblasts recover after 10 Gy irradiation faster than control fibroblasts Skin fibroblasts were isolated from eight male bank voles from the Chernobyl exclusion zone and from an uncontaminated control area near Kiev
To assess if Chernobyl fibroblasts tolerate more oxidant because they had more antioxidants, total antioxidant levels were measured by cell extracts’ capacity to reduce copper
Summary
Elevated levels of environmental ionizing radiation can be a selective pressure for wildlife by producing reactive oxygen species and DNA damage. The most contaminated area around the nuclear power plant has been closed to the general public This Chernobyl exclusion zone covers about 2600 km and still contains patches of radioactively contaminated soil emitting from normal background levels of 0.2 μSv/h up to about 200 μSv/h [1]. A meta-analysis has shown that ionizing radiation has increased mutation frequency in various Chernobyl taxa as represented by, for example, discolorations, cataracts, chromosomal abnormalities, or cancers [2]. Another meta-analysis on wildlife inhabiting Chernobyl area found a small to intermediate increase in oxidative damage (such as imbalance between oxidants and antioxidants) and a decrease in antioxidant defenses (such as depleted antioxidant levels) [3]. Adaptation has been reported in plants: plants within Chernobyl area have higher resistance to DNA-damaging chemicals, antioxidants, osmotic stress, and gamma irradiation
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