Effect of nicotine and its metabolized form on primary mouse embryonic fibroblast cell line (PMEF) in vitro

Abstract

Nicotine is the principal alkaloid found in tobacco and 70%-80% is converted to cotinine. Like nicotine, cotinine can rapidly pass through the placenta from mother to child by transplacental transfer which occurs throughout pregnancy. Epidemiological research has found a statistically significant association between maternal smoking and the occurrence of oral clefts in newborns. In this study, the PMEF cell line (E13) was selected to represent mesenchymal cells at embryonic day 13 (E13) in mice, which coincides with the elevation of the palatal shelves marking a critical time in palatogenesis. This study aims to investigate the effects of nicotine, cotinine, and their combination on ROS generation, cell viability, cell apoptosis, and apoptosis-related gene expression in PMEF cells in vitro. Results showed that nicotine and cotinine had an adverse effect on PMEF cells through decreased cell viability and increased apoptotic cell death in a dose-dependent manner. Nicotine, cotinine, and the combination of them significantly increased the generation of ROS. Overproduction of ROS was closely associated with the number of viable cells, apoptotic cells, and the expression of apoptosis- related PMEF genes, such as CAS3 and P53, which induce apoptosis. Interestingly, this study also found that cotinine enhanced the cytotoxic effect of nicotine treatments by decreasing cell viability, activating cell apoptosis by increasing ROS production and expression of CAS3 and P53.

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