Evaluation of aluminum absorption in Caenorhabditis elegans: pre-treatment optimization and the impact of dose and population size

Abstract

Accurate quantification of aluminum (Al) uptake is essential for evaluating metal toxicity in experimental models. This study aimed to optimize pretreatment strategies and determine the effects of individual number and dose on Al accumulation and assess the biological relevance of Al exposure in the Caenorhabditis elegans model. The investigation was conducted in two stages. In the first stage, synchronized groups of 10, 25, 50, 100, 200, and 400 worms, along with controls, were exposed to 10, 15, and 25 mM AlCl₃ for seven days After exposure, worms were washed to remove Al from the culture medium, viability was terminated using nitric acid, and Al levels were quantified by ICP-MS without pretreatment. In the second stage, 50 worms exposed to 100 mM AlCl₃ for seven days and subjected to four different pretreatment protocols prior to ICP-MS analysis. Reproductive toxicity was additionally evaluated to determine the biological impact of Al accumulation. Significant dose-dependent increases in Al uptake were observed, particularly in groups containing 10, 25, and 50 worms (first trial). Among pretreatment methods (second trials), the combined sonication and centrifugation supernatant protocol yielded the highest Al levels (78.47 mM), followed by pretreatment A (68.68 mM), C (64.52 mM), and B (59.60 mM). Furthermore, Al exposure significantly reduced reproductive capacity compared with controls These findings demonstrate that both organism number and pretreatment strategy critically influence Al quantification and confirm that accumulated Al is associated with biologically relevant toxic effects. The optimized methodology provides a robust framework for future metal toxicity studies.