Protective effect of capsaicin on alleviating ethanol-induced oxidative gastric mucosal injury via mediation of the CCR4/Src/p47phox signaling pathway both in vitro and in vivo

Background Ethanol is a common trigger for gastric mucosal diseases, and ethanol-induced oxidative damage to the gastric mucosa can lead to diseases such as gastritis, gastric ulcer and gastric cancer. Counteracting oxidative stress is crucial for the attenuation of gastric mucosal damage. While capsaicin, a biologically safe small molecule, has been identified to counteract oxidative damage in the gastric mucosa, its exact mechanism remains indeterminate. Purpose This research seeks to elucidate the prophylactic efficacy and the molecular mechanism of capsaicin against oxidative damage to the gastric mucosa. Methods With network pharmacology method, we investigated the targets influenced by capsaicin in mitigating gastric mucosal damage. We established an ethanol-induced oxidative gastric mucosal injury model using GES-1 and RAW264.7 cells. Subsequently, we assessed the impact of capsaicin pretreatment on the expression of genes related to the chemokine pathway and its modulation of the NF-κB pathway through western blot, reverse transcription-quantitative PCR, immunofluorescence techniques and enzyme linked immunosorbent assay. Lastly, in rat model, we examined capsaicin’s protective role on the gastric mucosa and observed alterations in key proteins associated with the chemokine pathway and inflammatory markers. Results In vitro experiments showed that capsaicin pretreatment suppressed both the transcription of chemokine receptor 4 (CCR4) and the expression of Src and p47phox, especially in Raw264.7. Furthermore, it impeded the phosphorylation and nucleation of the NF-κB p65 protein within the NF-κB signaling pathway and inhibits cytokine expression. In vivo experiments exhibited that pretreatment with capsaicin counteracted ethanol-induced disruptions in the glandular structure of gastric tissues, curtailed the infiltration of macrophages and neutrophils, and prevented epithelial cell detachment, thereby effectively shielding the gastric mucosa. Consistent with the in vitro results, capsaicin markedly reduced the expression level of CCR4, Src and p47phox induced by ethanol in the gastric mucosa. Moreover, capsaicin could reduce the level of P-p65 in the gastric mucosa, which in turn inhibited the expression of CXCL1/KC (IL-8), TNF-α, IL-6, and IL-1β, and boosted the levels of the anti-inflammatory agent IL-10 in serum. Conclusion This research revealed that capsaicin mitigates ethanol-induced gastric mucosal injuries by suppressing the CCR4/Src/p47phox axis, thereby reducing oxidative stress, and by curtailing the phosphorylation modification of NF-κB p65 and its nuclear translocation, leading to diminished inflammatory responses. These insights elucidate capsaicin’s mechanistic pathways and offer theoretical backing for its therapeutic application in treating gastric mucosal injuries.