Physiological Effects of Nicotine and Lead (II) Acetate on Zebrafish Embryo Development

Abstract

E-cigarettes have become increasingly popular in the United States, with the Centers for Disease Control and Prevention (2023) reporting that a 47% increase in e-cigarette sales at US retail outlets from 2019 through 2023. Additionally, Vilcassim et al. (2023) estimate that 2.2% to 7% of pregnant women use e-cigarettes, potentially exposing their developing fetus to harmful chemicals. While most existing literature has studied the effect of nicotine alone, this study investigates the interplay of two key e-cigarette components—nicotine and lead (II) acetate—on embryonic development using a zebrafish (Danio rerio) model. Zebrafish embryos were divided into four groups, each raised in a 10 mL solution: control (embryo medium), 5 μM nicotine, 5 μM lead (II) acetate, and a combination of 5 μM nicotine and 5 μM lead (II) acetate. They were observed from 0-5 days post-fertilization (dpf). Heart rate and spinal curvature data were measured at 5 dpf. The embryos were then euthanized, and their craniofacial cartilage was analyzed via Alcian blue staining. Results showed a significant reduction in heart rate in the combined group compared to the control; however, spinal curvature and craniofacial cartilage data were inconclusive. Despite these mixed findings, the observed embryonic deformities underscore the dangers of ecigarettes and the need for further research on the developmental impacts of their ingredients.