Assessment of the effect of physical and chemical factors at doses of 1.5 MAC/MEL on the relative length of Wistar rat telomeres in a chronic experiment

Le résumé fourni par la source

Reduction in relative telomere length (RTL) is considered a key biomarker of cellular aging and is associated with exposure to adverse environmental and occupational factors. The aim of the study was to assess the dynamics of TL decrease in Wistar rats under isolated, combined, and combined-action of physical (general vibration, noise) and chemical (mixture of hydrocarbons) factors at a level of 1.5 MAC/MEL in a chronic experiment. Material and methods. A 180-day chronic experiment was conducted on male Wistar rats (n = 95). The animals were divided into 6 groups of 15 individuals: G1 (general vibration), G2 (noise), G3 (mixture of chemicals: dimethylbenzene, gasoline, methylbenzene, propan-2-one), G4 (combined exposure: vibration + noise), G5 (combined exposure: vibration + noise + chemicals), and G6 (intact control). The exposure was carried out for 0.5 hours per day, 5 days a week. Five individuals were selected for background control. RTL was determined in the DNA of the striated muscle tissue of the thigh using quantitative real-time PCR on days 0, 60, 120, and 180 of the experiment. Results. I n the control group (G6), a significant RTL reduction compared to the initial level was recorded only by the 180th day, which reflects the natural processes of aging. The most pronounced effect was observed in the group of isolated chemical exposure (G3), where a significant telomere shortening was noted as early as on the 60 th day (1.51 [1.39; 1.57] relative units, p < 0.05). The isolated exposure to vibration (G1) and noise (G2) led to a statistically significant reduction in RTL on the 120 th and 180 th days. Combined (G4) and combined-sequential (G5) exposure also caused a significant shortening of the OD at 120 and 180 days relative to the control, but no statistically significant differences in the degree of shortening were observed between all the experimental groups at the same time points. Conclusions. Chronic exposure to physical and chemical factors at a level of 1.5 MAC/MRL induces accelerated reduction in RTL in laboratory animals. Chemical factors have the earliest and most pronounced effect. The absence of intergroup differences between the experimental groups may indicate that a threshold level of damage has been reached, leading to the maximum possible telomere shortening under these conditions. These findings suggest that RTL can be used as a promising biomarker for assessing the risks of accelerated aging associated with occupational hazards.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.