Evaluation of the initial manifestations of the toxic process in conditions of chronic action of low subtoxic doses of dioxins polluting the environment

AIM: To study the state of the genome by indicators of retrotransposon activity the gene encoding DNA methyltransferase 1 (DNMT1); DNA damage in animals from the natural population of the bank vole (Clethrionomys glareolus) living in the vicinity of a preserved landfill contaminated with low concentrations of dioxins (landfill of production and consumption waste "Salariyevo", Moscow).MATERIAL AND METHODS: The activity of ERV-L, B1, and L1 retrotransposons and the transcription level of the DNMT1 gene were evaluated by real-time PCR. The stability of DNA in liver and bone marrow cells was characterized by the comet assay method. Afterward, the obtained characteristics of the state (stability, reactivity, and damage) of the genome in response to environmental stress factors were compared in groups of animals from the study and conditionally control samples.RESULTS: The effects of a decrease in the activity of retrotransposons of classes B1 and L1, and an increase in DNMT1 gene expression level were revealed in voles from the natural population living under the long-term chronic exposure to low doses of dioxins decrease in the activity of retrotransposons of classes B1 and L1, and an increase in the expression level of the DNMT1 gene were revealed. An increased level of DNA damage (on average up to 56% of the DNA in the tail of the comet) was detected in hepatocytes, with the addition of winter environmental factors to the chronic effect of small subtoxic doses of dioxins.CONCLUSION: Suppression of retrotransposon activity and increased expression of its epigenetic regulator (DNMT1) are regarded as adaptive responses to long-term chronic exposure to low doses of dioxins polluting the environment. The alteration in the reactivity and destabilization of the genome indicates the launch of the initial mechanisms of the toxic process formation. The created and tested methodological base for its study opens up prospects for establishing a threshold level, and as a result, substantiating indicators for screening assessment of local (territorial) risk to public health by biomonitoring

Biology · Environmental health · Physics · Waste management · bioluminescence and chemiluminescence research · Chemistry · Computer Science · Engineering · Environmental Science · Medicine · Toxic Organic Pollutants Impact · Environmental Chemistry · Toxicology

• Dioxins in the Environment and the Body of Animals Near Landfill

  Open Access•Roumak, V S Roumak et al.•Ekologiya Cheloveka (Human Ecology•2017

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