Electroacupuncture protects the intestinal mucosal barrier in diarrhea-predominant Irritable Bowel Syndrome rats by regulating the MCs/Tryptase/PAR-2/MLCK pathway.

OBJECTIVE: The pathogenesis of diarrhea-predominant irritable bowel syndrome (IBS-D) is related to damage to the intestinal mucosal barrier function. Based on the Mast cell (MC)/Tryptase/Protease-activated receptor-2 (PAR-2)/Myosin light chain kinase (MLCK) pathway, this study explored the effect of electroacupuncture (EA) on IBS-D rats and its possible mechanism of protecting the intestinal mucosal barrier. METHODS: The IBS-D rat model was established by mother-offspring separation, acetic acid enema, and chronic restraint stress. The efficacy of EA on IBS-D rats was evaluated by observing the rate of loose stool (LSP) and the minimum volume threshold of abdominal withdrawal reflex (AWR) in rats. Mast cells and the ultrastructure of intestinal mucosa were observed by H&E staining, toluidine blue staining, and transmission electron microscopy. The expression levels of Tryptase, PAR-2, MLCK, zonula occludens-1 (ZO-1), and Occludin in rats were detected by ELISA, qRT-PCR, and western blot. RESULTS: After 7 days of intervention, compared to the IBS-D group, the loose stool rates of rats in IBS-D + EA group and IBS-D + ketotifen group were decreased (P < 0.01), the minimum volume thresholds of AWR were improved (P < 0.01), the inflammation of colon tissue decreased, the number of MCs were decreased (P < 0.01), the expression of Tryptase, PAR-2, and MLCK were lowered (P < 0.01, P < 0.05), and the expression of ZO-1 and Occludin were enhanced (P < 0.01, P < 0.05). Compared to the EA group, there was no significant difference in each index between the ketotifen groups (P > 0.05). CONCLUSION: EA has a good therapeutic effect on IBS-D rats. Regulating the MCs/Tryptase/PAR-2/MLCK pathway may be a mechanism to protect the intestinal mucosal barrier.

[Protective mechanism of electroacupuncture combined with acellular nerve allografts on spinal ganglia in rats with sciatic nerve injury].

OBJECTIVE: To observe the effects of electroacupuncture (EA) combined with acellular nerve allograft (ANA) on the morphological structure of spinal ganglion cells and the protein expressions of nerve growth factor (NGF) and phosphorylated protein kinase B (p-Akt) in rats with sciatic nerve injury (SNI), so as to explore the protective mechanism of EA combined with ANA on spinal ganglia. METHODS: SPF male SD rats were randomly divided into normal, model, single ANA bridging (bridging) and EA + ANA (combination) groups， with 10 rats in each group. The SNI rat model was established by right sciatic nerve transection. Rats in the bridging group were bridged with ANA to the two broken ends of injured sciatic nerves. Rats in the combination group were treated with EA at "Yanglingquan" (GB34) and "Huantiao" (GB30) 2 d after ANA bridging, with dilatational wave, frequency of 1 Hz/20 Hz, intensity of 1 mA, 15 min/d, 7 d as a course of treatment for 4 consecutive courses. Sciatic function index (SFI) was observed by footprint test. Wet weight ratio of tibialis anterior muscle was calculated after weighing. Morphology of rat spinal ganglion cells was observed after Nissl staining. The protein expressions of NGF and p-Akt were detected by immunofluorescence and Western blot. RESULTS: Compared with the normal group, the SFI and wet weight ratio of tibialis anterior muscle were significantly decreased (P<0.05), the number of Nissl bodies in spinal ganglion cells was significantly reduced (P<0.05) with dissolution and incomplete structure， the protein expressions of NGF and p-Akt in ganglion cells were significantly decreased (P<0.05) in the model group. Following the interventions and in comparison with the model group, the SFI and the wet weight ratio of tibialis anterior muscle were significantly increased (P<0.05), the damage of Nissl bodies in ganglion cells was reduced and the number was obviously increased (P<0.05), and the protein expressions of NGF and p-Akt in ganglion cells were significantly increased (P<0.05) in the bridging and combination groups. Compared with the bridging group, the SFI and the wet weight ratio of tibialis anterior muscle were increased (P<0.05), the morphology of Nissl bodies in ganglion cells was more regular and the number was increased (P<0.05), the protein expressions of NGF and p-Akt in spinal ganglion cells were significantly increased (P<0.05) in the combination group. CONCLUSION: EA combined with ANA can improve the SFI and the wet weight ratio of tibialis anterior muscle in SNI rats, improve the morphology and structure of Nissl bodies in spinal ganglion cells, and increase the protein expressions of NGF and p-Akt in spinal ganglion, so as to play a protective role on spinal ganglia.