Assessment of the embryotoxic potential of electronic cigarette fluid using the Zebrafish Embryotoxicity Test (zfet)

Abstract

Electronic cigarettes have recently gained popularity as a nicotine delivery device. Due to the fact that they deliver nicotine without the combustion of tobacco, they are popularly promoted as a safer alternative to traditional cigarette smoking, despite the lack of scientific consensus on their possible adverse effects. Previous studies have attempted to investigate the possible adverse effects of electronic cigarettes, with some studies characterizing their possibly toxic components. This study attempted to identify the components in the electronic cigarette fluid sample selected and to determine the embryotoxic potential of the fluid as a whole. Sixty (60) mg of the electronic cigarette fluid sample was suspended in 1.5 mL DCM solvent and subjected to gas chromatography-mass spectrometry (GC-MS). Four main constituents were identified, and the sample was then utilized in the zebrafish embryotoxicity (ZFET) test. Lethal and sublethal endpoints were observed in the zebrafish embryos. Absence of heartbeat, coagulation, non-formation of somites, and non-detachment of tail were the lethal endpoints observed in the exposed embryos, while delayed hatching, pericardial edema, and yolk sac edema were the sublethal endpoints observed in the embryos exposed. Low dilutions were found to be highly embryotoxic and a dose-response relationship was seen in dilutions ranging from 1:30 to 1:140. The LC50 of the electronic cigarette mixture was also obtained and found to be 0.36568 mL or 1:66 dilution. The results of the study determined that the electronic cigarette fluid was significantly embryotoxic, and that further studies are recommended to determine the possible mechanisms of the observed toxicity responses in zebrafish embryos.