Andrographolide sodium bisulfate attenuates UV‑induced photo‑damage by activating the keap1/Nrf2 pathway and downregulating the NF‑κB pathway in HaCaT keratinocytes

Abstract

Oxidative and inflammatory damage has been suggested to play important roles in the pathogenesis of skin photoaging. Andrographolide sodium bisulfate (ASB) is a soluble derivative of andrographolide and has known antioxidant and anti‑inflammatory properties. In the present study, cellular experiments were designed to investigate the molecular mechanisms underlying the effect of ASB in relieving ultraviolet (UV)-induced photo-damage. Following ASB pretreatment and UV irradiation, the apoptosis and necrosis of HaCaT cells were investigated by Hoechst 33342/propidium iodide staining. Reactive oxygen species (ROS) production was investigated using a DCFH-DA fluorescence probe. Furthermore, the protein expression levels of p65, NF-κB inhibitor-α, nuclear factor E2-related factor 2 (Nrf2) and kelch-like ECH-associated protein 1 (keap1) were measured via western blotting and immunofluorescence analyses. Furthermore, NF-κB-mediated cytokines were assessed by ELISA, and Nrf2-mediated genes were detected by reverse transcription-quantitative PCR. Pretreatment with ASB markedly increased cell viability, decreased cell apoptosis and decreased UV-induced excess ROS levels. In addition, ASB activated the production of Nrf2 and increased the mRNA expression levels of glutamate-cysteine ligase catalytic subunit and NAD(P)H quinone oxidoreductase 1, while ASB downregulated the protein expression of p65 and decreased the production of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α. These results suggested that ASB attenuates UV-induced photo-damage by activating the keap1/Nrf2 pathway and downregulating the NF-κB pathway in HaCaT keratinocytes.