Establishing a Neuronal Cell Model to Probe the Toxicity of Commonly Used Phthalate-free Alternatives

Phthalate plasticizers are noncovalently bound chemicals widely used to impart flexibility into plastics in a variety of products including plastic food wrap, personal care products, toys, and medical tubing. Phthalates have been shown to leach out of these plastic products and compromise organismal health by disrupting the nervous and reproductive systems. As a result of these detrimental effects, non-phthalate plasticizers have been developed and are being used as alternatives, but the impacts of phthalate-free alternative plasticizers on organisms have not been extensively tested. Thus, our goal was to examine the effects of the alternative plasticizer Acetyl tributyl citrate (ATBC), commonly found in medical devices, cosmetics, and children’s toys, on neurons using the mouse neuroblastoma cell line, Neuro2a cells. Previous studies in our lab determined that at concentrations ranging from 10-200 μM ATBC resulted in a decreased number of Neuro2a cells after three days. To further examine the mechanism mediating the decrease in cell number, we continued this study by examining effects on cell cycle arrest and senescence pathways using flow cytometry, quantitative reverse transcriptase PCR, and the senescence associated β-galactosidase expression assay. Together, our results suggest that ATBC is causing stress-induced premature senescence in dividing Neuro 2a cells, as well as death-evoking effects in terminally differentiated neurons. In the context of the aging brain and neurodegenerative diseases, this could have profound implications when considering the outcomes of increased loss of glial cell function via senescence as well as increased neuronal cell death