[Danggui Buxue Decoction delays vascular endothelial cell senescence induced by intermittent hypoxia through...

This study aims to explore the antioxidant molecular mechanism of Danggui Buxue Decoction(DBD) in delaying the vascular endothelial cell senescence induced by intermittent hypoxia(IH). The C57BL/6N mouse model of chronic intermittent hypoxia(CIH) was established under 5%-21% O_2, 20 cycles·h~(-1), 8 h·d~(-1) and administrated with DBD(4.68 g·kg~(-1)·d~(-1)) by gavage. The IH model of mouse thoracic aortic endothelial cells was established(0.1% O_2 3 min-21% O_2 7 min, 6 cycles·h~(-1)). The cells were then treated with the antioxidant N-acetylcysteine(NAC), DBD-containing serum, or DBD-containing serum plus nuclear factor-erythroid 2-related factor 2(Nrf2) siRNA. The vascular function, pathological changes, and the aging condition of the aorta tissue in mice were detected. The senescence status of cells, the level of oxidative stress, mitochondrial membrane potential, and the apoptosis level were measured via commercial kits. The expression levels of silent information regulator 1(SIRT1), tumor protein p53, superoxide dismutase 2(SOD2), nicotinamide adenine dinucleotide phosphate oxidase 2(NOX2), Kelch-like ECH-associated protein 1(Keap1), Nrf2, heme oxygenase-1(HO-1), B cell-lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and cysteinyl aspartate-specific proteinase-3(Caspase-3) were determined by Western blot or Real-time fluorescence quantitative PCR. The results showed that DBD significantly improved the vascular function and attenuated the vascular endothelial damage and senescence in mice. Compared with the IH group, 5% DBD-containing serum or 1 mmol·L~(-1) NAC significantly increased the proliferation level of endothelial cells, promoted the expression of SIRT1, Nrf2, and HO-1 at protein and mRNA levels in endothelial cells, raised the expression level of SOD2, the mitochondrial membrane potential, and the mRNA level of Bcl-2, while significantly reducing the number of senescent cells, the expression of p53 and Keap1 at protein and mRNA levels, the content of reactive oxygen species in endothelial cells, the protein level of NOX2, and the mRNA levels of Bax and Caspase-3. The above-mentioned therapeutic effects were inhibited after intervention with Nrf2 siRNA. These results suggest that DBD alleviates the oxidative stress and inhibits the apoptosis of endothelial cells by activating the Nrf2 signaling pathway, thereby slowing down endothelial cell senescence under IH exposure.