Effect of electroacupuncture on acute gastric mucosal injury in mice by regulating macrophage polarization mediated by the cGAS-STING signaling pathway

To observe the effect of electroacupuncture on mice with acute gastric mucosal injury (AGMI) by regulating macrophage polarization through the cyclic guanosine monophosphate-adenosine synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway.

Thirty C57BL/6 mice were randomly divided into normal group, model group, and electroacupuncture group. Except for the normal group, the remaining mice were intragastrically administered with absolute ethanol to establish the AGMI model. Mice in the electroacupuncture group were treated with electroacupuncture at “ Zhongwan” (CV12) and “Zusanli” (ST36) for 30 min, once a day for 5 consecutive days. The Guth gastric mucosal injury scoring method was used to evaluate gastric mucosal injury. HE staining and PAS staining were performed to observe the pathological changes of gastric mucosal tissue. Flow cytometry was used to analyze the proportions of M1 and M2 macrophages in gastric mucosal tissue. Real-time quantitative PCR was used to detect the mRNA expression levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and transforming growth factor-β (TGF-β) in gastric mucosal tissue. Western blot was used to detect the protein expression levels of zonula occludens-1 (ZO-1), Occludin, cGAS, STING, phosphorylated STING (p-STING), phosphorylated interferon regulatory factor 3 (p-IRF3), phosphorylated TANK-binding kinase 1 (p-TBK1), inducible nitric oxide synthase (iNOS), cluster of differentiation 86 (CD86), arginase-1 (Arg-1), and cluster of differentiation 206 (CD206). Immunofluorescence was used to detect the fluorescence intensity of iNOS and CD206 in gastric mucosal tissue.

Compared with the normal group, the model group showed an increased gastric mucosal injury index (P<0.01), with epithelial necrosis, glandular disorder, and mucus layer destruction in the gastric mucosa; the number of M1 macrophages increased while M2 macrophages decreased (P<0.01); the mRNA expression levels of TNF-α and IL-6 were increased (P<0.01), while the mRNA expression levels of IL-10 and TGF-β were decreased (P<0.01); the protein expression levels of ZO-1 and Occludin were significantly decreased (P<0.01); the proteins related to the cGAS-STING pathway, as well as iNOS and CD86 were up-regulated (P<0.01), while Arg-1 and CD206 were down-regulated (P<0.01) in gastric mucosal tissue. Compared with the model group, all the above mentioned indicators in the electroacupuncture group were significantly reversed (P<0.01, P<0.05), with reduced pathological damage and a relatively intact mucus layer in gastric mucosa.

Electroacupuncture can alleviate gastric mucosal inflammation and improve AGMI, and its mechanism may be related to inhibiting MI macrophage polarization mediated by the cGAS-STING signaling pathway.