Comparative assessment of isolated influence exerted by physical and chemical factors on relative telomere length of laboratory animals in a model experiment

Assessment of effects produced by physical and chemical occupational factors on changes in the relative telomere length (RTL) in workers is a promising trend in contemporary research. It can be used as a marker of not only ageing but also intensity of oxidative stress and chronic inflammation. Simulation of such effects in experiments on laboratory ICR mice and Wistar rats enriches our knowledge on the subject. In this study, we were interested in performing comparative assessment of isolated effects produced by physical and chemical factors on the relative telomere length of laboratory animals in a model experiment. The study involved using laboratory animals (mice, n = 65; rats, n = 65) divided into the experiment (total vibration, noise and a mixture of aromatic hydrocarbons) and the control groups. Animals in the control group were intact. Exposure to chemical and physical factors was simulated in a model animal experiment. The relative telomere length was established using the quantitative real-time polymerase chain reaction. The experimental data were analyzed by non-parametric analysis techniques in Statistica 10 software package. Intergroup differences were estimated using the Mann - Whitney test. Critical significance in testing of statistical hypotheses was taken below 0.05. Physical and chemical factors had the greatest influence on RLT shortening in the experimental animals relative to the control (intact animals). This indicates activation of the accelerated ageing pathways and growing risks of diseases associated with these exposures. The fastest RLT shortening rates were established upon exposure to total vibration and the chemical factor in mice after 30 days in the experiment; rats, after 60 days. The maximum growth in RLT shortening upon exposure to noise was established in mice after 60 days in the experiment; rats, after 180 days. Differences in RLT in comparison with its initial value were lost in mice on the 90th day in the experiment and in rats on the 180th day of the modeled chemical and physical exposure, which may be interpreted as overall ageing of the experiment animals. RLT shortening in biological objects upon long-term exposure to adverse chemical and physical factors gives evidence of accelerated ageing of the biological systems in the body and can create elevated risks of cardiovascular and aging-associated diseases.