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Effective concentrations of selenium pre-treatment in mitigating cadmium-induced cardiotoxicity in zebrafish (Danio rerio)
Location: 76
Mentor: Dr. Delia Shelton
Cadmium (Cd) is a toxic heavy metal and environmental contaminant linked to cardiovascular diseases with increasing human exposure due to industrial activities. Zebrafish (Danio rerio) are used as a model to study Cd cardiotoxicity because their cellular development and heart properties are similar to mammals and they are suitable for large scale screening studies. In zebrafish, Cd induces pericardial edemas and bradycardia, highlighting the need for protective interventions. Selenium (Se), an essential trace element, has been proposed as a potential therapeutic agent against Cd toxicity, but its protective ability remains unclear. This study investigated the effects of Se pre-treatment on Cd-induced cardiotoxicity using zebrafish embryos because zebrafish share ~70% genetic homology with humans. Embryos were exposed to Se (0, 10, 50, 100, 150, or 200 µg/L) for 1-4 days before exposure to Cd (0, 2.5 or 5 µg/L). Kruskal-Wallis chi-squared with Dunn’s Multiple Comparisons post-hoc tests were used to analyze pericardial edema results. ANOVA with Tukey HSD post-hoc and independent samples t-tests were used to analyze heart rate results. Results demonstrated that 50 µg/L Se pre-treatment significantly reduced pericardial edema and mitigated bradycardia at 2.5 µg/L Cd but was ineffective at 5 µg/L Cd. Additionally, longer Se pre-treatments (3–4 days) provided significantly greater cardioprotection than shorter pre-treatments (1–2 days), indicating that duration plays a crucial role in Se efficacy. However, higher Se concentrations (>100 µg/L) increased incidences of pericardial edema than lower concentrations, suggesting a narrow therapeutic range. Lastly, Se pre-treatment ameliorated bradycardia at 2.5 µg/L Cd. These findings confirm Se pre-treatment can mitigate Cd-induced cardiotoxicity in a dose- and time-dependent manner, with Se concentrations < 100 µg/L maximizing the benefits while avoiding toxicity.
