Analysis of toxicity effects of Di-(2-ethylhexyl) phthalate exposure on human bronchial epithelial 16HBE cells

Recent studies have indicated that Di-(2-ethylhexyl) phthalate (DEHP), the most commonly used plasticizer in daily-life products, could be dispersed in indoor air and induce human exposure via inhalation. DEHP has been reported to have effects on the respiratory system in both animal and human researches. The toxicity effects of DEHP exposure on cell proliferation, cell cycle progression, apoptosis, global DNA methylation and the expression levels of DNA methyltransferases (DNMTs) were investigated in this study, using human epithelial cell line 16HBE as an in vitro model. Cells were treated with DEHP at doses of 0, 0.125, 0.5 and 2 mmol/L for 48 h. Cell proliferation, cell cycle and apoptosis were tested by MTT assay and flow cytometer, respectively. The obtained results showed decreased living cell number and cell viability following DEHP exposure at the dose of 2 mmol/L. DEHP also inhibited the cell cycle progression of G1 phase and induced a significant increase in cell apoptosis in 16HBE cells. DEHP exposure could induce cell proliferation inhibition in 16HBE cells via the blocking of cell cycle progression and accelerated cell apoptosis. In addition, decreased global DNA methylation levels and expression levels of DNMTs were observed in DEHP-treated groups which revealed possible epigenetic effects of DEHP.