Irigenin alleviates angiotensin II-induced oxidative stress and apoptosis in HUVEC cells by activating Nrf2 pathway

Endothelial dysfunction is closely related to various cardiovascular diseases. Oxidative stress and apoptosis are involved in the progress of endothelial dysfunction. Irigenin (IR) has antioxidative properties. We investigated IR as a novel therapy for angiotensin II (Ang II)-induced endothelial dysfunction and explored the potential mechanisms of IR. After human umbilical vein endothelial cell lines (HUVECs) were treated with Ang II (100, 200, 300 and 400 nmol/L) alone, IR (2.5, 5, 10, 20 and 40 mu mol/L) alone or Ang II plus IR for 24 h, HUVECs viability, lactate dehydrogenase (LDH), apoptosis, oxidative stress, apoptosis-related protein and nuclear factor E2-related factor 2 (Nrf2) levels were detected by Cell Counting Kit (CCK)-8 assay, enzyme-linked immunosorbent assay, flow cytometry and western blot. Transfection rate of Nrf2 was detected by western blot. In the next rescue experiment, we used silent Nrf2 (siNrf2) to verify the previous experimental results. Different concentrations' Ang II repressed HUVECs viability and increased LDH release, and different concentrations' IR did not affect HUVECs viability or LDH release. Furthermore, IR elevated cell viability and Nrf2 level, inhibited LDH release, apoptosis, oxidative stress and apoptosis-related protein levels in Ang II-induced HUVECs. More important, siNrf2 suppressed the expression of Nrf2, and siNrf2 abrogated the protective effect of IR on Ang II-induced Nrf2 expression, cell viability, LDH activity, oxidative stress generation and apoptosis-related protein in HUVECs. IR protected HUVECs from Ang II-induced oxidative stress and apoptosis injury by activating Nrf2 pathway.