Objective To study the effect of coal tar pitch extract on the expressions of Nrf2, Keap1, NQO1 mRNA and Nrf2 protein in BEAS-2B cells, and to explore the target genes and pathway in defense against cell oxidative damage caused by coal tar pitch.
Methods GC-MS was applied to analyze the ingredients of coal tar pitch (CTP)extract. According to literature and previous experiments, BEAS-2B cells were exposed separately to different concentration of CTP extract, namely 0.00, 1.25, 2.50, 5.00, and 10.00 mg/L in the acute cell toxicity test. The proliferation of BEAS-2B exposed to the extract of CTP was analyzed by MTT. The reverse transcription polymerase chain reaction (RT-PCR)was applied to measure the expressions of Nrf2, Keap1 and NQO1 mRNA, and Western blot was used to determine the level of Nrf2 protein.
Results The main ingredients of coal tar pitch extract were polycyclic aromatic hydrocarbon compounds, accounted for 86.02%, which promoted cell proliferation in the 1.25 mg/L concentration and restrained cell proliferation in the concentrations 2.5-10 mg/L. The expressions of Nrf2 mRNA and protein in all test groups were lower than those in the control group while the expressions of Keap1 mRNA was higher than control with significant statistical difference (P < 0.05). The expressions of Nrf2 increased with increasing concentration of CTP extract, however, it decreased in the 10.00 mg/L group. The expression level of NQO1 mRNA increased gradually with increasing concentration of CTP extract among the concentrations 2.5-10 mg/L.
Conclusion The ability against antioxidant stress might be enhanced through the Nrf2-Keap1/ARE pathway when CTP extract stimulated the BEAS-2B cells.
DownLoad: