Electroacupuncture activates enteric glial cells and protects the gut barrier in hemorrhaged rats

Abstract

AIM: To investigate whether electroacupuncture ST36 activates enteric glial cells, and alleviates gut inflammation and barrier dysfunction following hemorrhagic shock. METHODS: Sprague-Dawley rats were subjected to approximately 45% total blood loss and randomly divided into seven groups: (1) sham: cannulation, but no hemorrhage; (2) subjected to hemorrhagic shock (HS); (3) electroacupuncture (EA) ST36 after hemorrhage; (4) vagotomy (VGX)/EA: VGX before hemorrhage, then EA ST36; (5) VGX: VGX before hemorrhage; (6) α-bungarotoxin (BGT)/EA: intraperitoneal injection of α-BGT before hemorrhage, then EA ST36; and (7) α-BGT group: α-BGT injection before hemorrhage. Morphological changes in enteric glial cells (EGCs) were observed by immunofluorescence, and glial fibrillary acidic protein (GFAP; a protein marker of enteric glial activation) was evaluated using reverse transcriptase polymerase chain reaction and western blot analysis. Intestinal cytokine levels, gut permeability to 4-kDa fluorescein isothiocyanate (FITC)-dextran, and the expression and distribution of tight junction protein zona occludens (ZO)-1 were also determined. RESULTS: EGCs were distorted following hemorrhage and showed morphological abnormalities. EA ST36 attenuated the morphological changes in EGCs at 6 h, as compared with the VGX, α-BGT and HS groups. EA ST36 increased GFAP expression to a greater degree than in the other groups. EA ST36 decreased intestinal permeability to FITC-dextran (760.5 ± 96.43 ng/mL vs 2466.7 ± 131.60 ng/mL, P < 0.05) and preserved ZO-1 protein expression and localization at 6 h after hemorrhage compared with the HS group. However, abdominal VGX and α-BGT treatment weakened or eliminated the effects of EA ST36. EA ST36 reduced tumor necrosis factor-α levels in intestinal homogenates after blood loss, while vagotomy or intraperitoneal injection of α-BGT before EA ST36 abolished its anti-inflammatory effects. CONCLUSION: EA ST36 attenuates hemorrhage-induced intestinal inflammatory insult, and protects the intestinal barrier integrity, partly via activation of EGCs.