Electroacupuncture accelerates the delayed intestinal transit in POI by suppressing M1 like muscularis macrophages and IL6 secretion

Background Electroacupuncture (EA) at ST-36 could accelerate the delayed gastrointestinal (GI) motility in many GI motility dysfunction models, but the definite effect and mechanisms are unclear. In this study, we intended to investigate the effects of EA on intestinal manipulation (IM) mice model and involved mechanisms. Methods Male C57BL/6 mice were randomized into five groups: normal control, intestinal manipulation (IM), IM with sham EA (SEA), IM with high-frequency EA (HEA), and IM with low-frequency EA (LEA). The GI transit was evaluated. The infiltration of muscularis macrophages (MM phi) and its phenotype were analyzed with flow cytometry. Magnetic-activated cell sorting was applied to isolate MM phi, and the relationship between the MM phi and interstitial cells of Cajal (ICCs) was further investigated. Results (1) Compared with the IM group, HEA and LEA attenuated the delayed intestinal transit. (2) Both the HEA and LEA obviously reduced the MM phi and suppressed the M1 activation of the MM phi in the ileum. (3) EA restored the disrupted ICC networks through inhibiting the release of IL6 by the MM phi. Conclusion (1) Electroacupuncture at acupoint ST-36 could accelerate the delayed intestinal transit in the IM murine model by restoring the ICC networks. (2) EA protected the ICCs through reducing the MM phi, inhibiting its M1 polarization and its IL6 secretion.

Automated summary

Both high-frequency and low-frequency electroacupuncture can alleviate delayed intestinal transit by reducing muscularis macrophages in the ileum and suppressing their M1 activation.