Early ageing in Caenorhabditis elegans caused by exposure to airborne benzene, toluene, ethylbenzene and xylenes (BTEX)

Air pollution is a major environmental and health concern. It has been linked to diseases and contributes to aging. However, there is a lack of studies on the effects of realistic mixtures of air pollutants, notably solvents. Therefore, we investigated the aging effects of benzene, toluene, ethylbenzene, and xylenes (BTEX) airborne exposure using the Caenorhabditis elegans (C. elegans) model, simulating a real scenario. Nematodes at larval stage four (L4) were exposed to benzene (0.9 ppm), toluene (40 ppm), ethylbenzene (25 ppm), and xylenes (17 ppm), either individually or in combination, for seven days in a chamber designed to contain volatile compounds. The results showed that the mixture caused early aging in nematodes, with decreased mobility and mitochondrial function on days 4 (15 % and 40 %), 7 (27 % and 10 %), and 10 (30 % and 5 %). The mixture also increased the damage to physiological and neuronal parameters on days 4 (26 % and 5 %), 7 (70 % and 43 %), and 10 (95 % and 25 %). The Frailty Index analysis revealed elevated values (index above 0.5) on all days in the mixture group compared to the control and isolated groups. The combination index demonstrated that synergism was predominant among the majority of the endpoints assayed. Our findings showed that low-level exposure to BTEX compounds could reduce the healthspan of C. elegans, reinforcing the utility of this model for aging and ecotoxicological studies, and underscoring the risks associated with prolonged exposure to BTEX pollutants in association.