Protective Effects of Safflor Yellow A Against H₂O₂-induced Oxidative Stress Injury in PC12 Cells via Nrf2/HO-1 Pathway

Background Safflor yellow (SY) is a water-capacitive component of dried flowers, mainly from safflor in the safflower family, which contains a large amount of bruthin A, or Safflor yellow A (SYA) for short. Studies have reported the protective effects of SYA against oxidative stress injury in nerve cells. Methods In this study, H2O2-treated PC12 cells were used as experimental materials to explore how SYA plays a protective role against nerve cells after oxidative stress and to analyze the molecular mechanism of SYA. PC12 cells were treated with H2O2 and SYA solution. Cell proliferation is then detected with Cell Counting Kit-8 (CCK-8). The detection method is 5-(and 6)-chloromethyl-2',7'-dichloro-dihydrofluorescein diacetate (CM-H2DCF-DA) staining reactive oxygen species (ROS). Levels of apoptosis-related proteins, including Bcl2-associated X protein (Bax), B-cell lymphoma (Bcl-2), caspase-3, and cleaved caspase-3, and oxidative stress regulators, namely, nuclear factor erythroid-2-related actor 2 (Nrf2) and heme oxygenase 1 (HO-1), were detected by western blotting. Results The CCK-8 assay results showed that the survival rate of H2O2-induced PC12 cells was significantly increased after SYA treatment. Fluorescence microscopy (CM-H2DCF-DA staining) indicated that SYA decreased H2O2-induced apoptosis in PC12 cells by reducing intracellular ROS. Western blotting analysis showed that SYA upregulated the expression of Nrf2, HO-1, and Bcl-2 and downregulated the expression of Bax, caspase 3, and cleaved caspase-3 in H2O2-induced PC12 cells. Conclusion SYA does protect the nerve cells from oxidative stress damage. Its mechanism of action is mainly related to whether the Nrf2/HO-1 pathway is activated.