ABSTRACT
AIM: To study the effects of tumor necrosis factor-α (TNF-α) on the transcriptional activity of nuclear factor-erythroid 2-related factor 2 (Nrf2) in pulmonary microvascular endothelial cells. METHODS: Rat pulmonary micro-vascular endothelial cells (PMVECs) were cultured by lung tissue block pasted methods, and identified immunocytochemically using Ⅷ factor-related antigen. The cells were treated with different doses TNF-α (prepared in serum-free medium) for 4 h. Subcellular localization and levels of Nrf2 in PMVECs were observed with immunocytochemical methods. Nuclear extract were obtained to assayed transcriptional activity of Nrf2 with EMSA. Total RNA were isolated to assay the mRNA expression of Nrf2 by RT-PCR. RESULTS: The protein level of Nrf2 in the nuclei and transcriptional activity increased dose-dependently in PMVECs after treated with TNF-α at concentrations of 2.5, 5.0 or 10.0 μg/L. However, the protein level of Nrf2 in nuclei and transcriptional activity decreased dose-dependently in PMVECs after treated with TNF-α at concentrations of 20 or 40 μg/L. No different mRNA expression of Nrf2 in PMVECs treated with TNF-α at all concentration above was observed. CONCLUSION: Transcriptional activity of Nrf2 increases in PMVECs treated with low or moderate doses of TNF-α and decreases in PMVECs treated with high doses of TNF-α.