Costunolide ameliorates MNNG-induced chronic atrophic gastritis through inhibiting oxidative stress and DNA damage via activation of Nrf2

Chronic atrophic gastritis (CAG) is a chronic digestive disease. Modern research has revealed substantial evidence indicating that the progression of CAG is closely linked to the occurrence of oxidative stress-induced DNA damage and apoptosis in the gastric mucosa. Additionally, research has indicated that Costunolide (COS), the primary active compound found in Aucklandiae Radix, a traditional herb, exhibits antioxidant properties. Nevertheless, the therapeutic potential of COS in treating CAG and its molecular targets have not yet been determined. The objective of this research was to explore the potential gastric mucosal protective effects and mechanisms of COS against N-Methyl-N´-nitro-N-nitrosoguanidine (MNNG)-induced CAG. Firstly, the MNNG-induced rat CAG model was established in vivo. Occurrence of CAG was detected through macroscopic examination of the stomachs and H&E staining. Additionally, we assessed oxidative stress, DNA damage, and apoptosis using biochemical detection, Western blot, immunohistochemistry and immunofluorescence. Then, an in vitro model was developed to induce MNNG-induced damage in GES-1 cells, and the occurrence of cell damage was determined by Hoechst 33342 staining and flow cytometry. Finally, the key targets of COS for the treatment of CAG were identified through molecular docking, cellular thermal shift assay (CETSA), and inhibitor ML385. In vivo studies demonstrated that COS promotes the expression of Nrf2 in gastric tissues. This led to an increased expression of SOD, GSH, HO-1, while reducing the production of MDA. Furthermore, COS inhibited DNA damage and apoptosis by suppressing the expression of γH2AX and PARP1 in gastric tissues. In vitro studies showed that COS effectively reversed apoptosis induced by MNNG in GES-1 cells. Additionally, COS interacted with Nrf2 to promote its expression. Furthermore, the expression levels of SOD, GSH, and HO-1 were augmented, while the generation of ROS and MDA was diminished. Our results indicate that COS exhibits therapeutic effects on CAG through the promotion of Nrf2 expression and inhibition of oxidative stress and DNA damage. Therefore, COS has the potential to provide new drugs for the treatment of CAG.