Acupuncture preconditioning at "Zusanli"(ST36) and "Zhongwan"(CV12) prevents stress gastric ulcer by regulating the TLR4/MyD88/IκB signaling pathway

Abstract

To observe the effect of electroacupuncture preconditioning at "Zusanli"(ST36，Lower Confluent point) and "Zhongwan"(CV12，Front-Mu point) combination on oxidative stress and inflammation-related indicators, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and inhibitor-α of nuclear transcription factor κB (IκB-α) in serum and gastric tissue of rats with stress gastric ulcer(SGU)，so as to explore its mechanisms underlying prevention of SGU. A total of 36 Wistar rats were randomly divided into blank control, model, positive drug and He-Sea-Front-Mu point combination groups (n=9 in each group). A rat model of SGU was established by restraint water-immersion stress method. Ten days before mode-ling, rats in the He-Sea-Front-Mu point combination group received electroacupuncture （2 Hz, 0.6 mA）at ST36 and CV12 for 10 min once every other day for 10 days, and those in the positive drug group was treated by gavage of omeprazole (20 mg/kg) once every other day for 10 days. The morphology of the gastric mucosa was observed by naked eyes and hematoxylin-eosin staining, and the ulcer index (UI) and lesion score were calculated. TBA and colorimetric methods, ELISA and Western blot were used to detect malondialdehyde (MDA), myeloperoxidase (MPO), glutathione peroxidase (GSH-Px), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels and the relative expressions of TLR4, MyD88, and IκB-α protein, separately. The gastric mucosa of rats in the blank control group was smooth and intact, the cells were arranged neatly, and there was no telangiec-tasia, hyperemia and inflammatory cell infiltration. The gastric mucosal epithelial structure of rats in the model group was destroyed, and a large number of mucosal epithelial cell death and inflammatory cell infiltration were seen. The degree of gastric mucosal injury and inflammatory cell infiltration in the positive drug group and the combined point group was less than that in the model group. Compared with the blank control group, the UI and lesion score of rats in the model group were significantly increased (P<0.05), the levels of MDA and MPO in the serum and gastric tissues were significantly increased (P<0.05), GSH-Px was significantly reduced (P<0.05), the contents of TNF-α and IL-6 in serum were markedly increased (P<0.05), the expression levels of TLR4 and MyD88 proteins in gastric tissue were significantly increased (P<0.05), IκB-α was significantly reduced (P<0.05). After intervention and in comparison with the model group showed that, the UI and lesion score, the levels of MDA and MPO, contents of serum TNF-α and IL-6, expression levels of TLR4 and MyD88 proteins in positive drug and He-Sea-Front-Mu point combination groups were significantly decreased (P<0.05), while GSH-Px and IκB-α were significantly increased (P<0.05); There were no significant differences in the above indicators between the positive drug and the He-Sea-Front -Mu point combination groups （except TNF-α）. Electroacupuncture preconditioning at ST36 and CV12 can prevent SGU, which may be related to its effects in anti-oxidant, anti-inflammatory and regulating TLR4/MyD88/IκB signaling pathway.