To observe the effect of electroacupuncture(EA) intervention on the interleukin-4 (IL-4)/Janus kinase 1 (JAK1)/signal transducer and activator of transcription 6 (STAT6) signaling pathway in colon tissue of chronic ulcerative colitis (UC) mouse model, in order to explore the potential mechanism of EA in promoting M2 macrophage polarization and improving intestinal mucosal barrier injury in UC mice.

A total of 56 eight-week-old SPF BALB/c mice (28 males and 28 females) were stratified by sex and randomly assigned to blank group (15 mice) and modeling group (41 mice). 3% DSS solution was used to induce the chronic UC model. The successfully induced mice were further divided into model, EA+11B11, and EA groups. Finally, 12 mice were included in each group. Mice in the EA+11B11 group received intraperitoneal injection of IL-4 inhibitor 11B11 (10 mg/kg) before EA, and mice in the EA group were treated with EA (10 Hz/50 Hz, 1 mA) at “Guanyuan” (CV4), “Tianshu” (ST25), “Zusanli” (ST36) and “Shangjuxu” (ST37) for 20 min. The treatments were performed once daily for 14 consecutive days. After the intervention, the following aspects were evaluated. ① Symptom improvement: including disease activity index (DAI) score, macroscopic morphology score in colon, and hematoxylin-eosin (HE) staining to observe the pathological changes in colon tissue; ②Structure and function of intestinal mucosal barrier: including the observation of colonic tight junction structure by transmission electron microscopy, detection of intestinal leakage by in vivo imaging with fluorescein isothiocyanate-4D (FITC-4D), detection of the positive expressions of tight junction protein ZO-1 and occludin in colon tissue by immunofluorescence staining; ③ Activation of IL-4/JAK1/STAT6 signaling pathway: detection of the relative expression levels of IL-4, p-JAK1/JAK1, and p-STAT6/STAT6 proteins in colon tissue by Western blot; ④ Markers of M2 macrophage polarization: detection of the CD206⁺/CD86⁺ ratio in mesenteric lymph nodes, and CD206 and arginase-1 (Arg-1) positive expressions in colon tissue by flow cytometry and immunofluorescence staining, respectively.

Compared with the blank group, mice in the model group showed significantly increased DAI score and macroscopic morphology score (P<0.05), disorganized colonic mucosal structure, severe intestinal fluorescence leakage, significantly decreased positive expressions of ZO-1 and occludin (P<0.05), reduced relative expression levels of IL-4, p-JAK1/JAK1, and p-STAT6/STAT6 proteins (P<0.05), as well as decreased CD206⁺/CD86⁺ ratio and positive expressions of CD206 and Arg-1 (P<0.05). Compared with the model group, the EA group exhibited reduced DAI and macroscopic morphology scores (P<0.05), improved colonic mucosal structure, and alleviated intestinal fluorescence leakage. The positive expressions of ZO-1 and occludin, and relative expression levels of IL-4, p-JAK1/JAK1, and p-STAT6/STAT6 proteins were significantly increased (P<0.05), along with elevated CD206⁺/CD86⁺ ratio, and CD206 and Arg-1 positive expressions (P<0.05). Compared with the EA group, the EA+11B11 group showed higher DAI and macroscopic morphology scores (P<0.05), disrupted colonic mucosal structure, obvious intestinal fluorescence leakage, decreased positive expressions of ZO-1 and occludin, and relative protein expression levels of IL-4, p-JAK1/JAK1, and p-STAT6/STAT6 (P<0.05), as well as reduced CD206⁺/CD86⁺ ratio, CD206 and Arg-1 positive expressions (P<0.05).

EA can promote the repair of colonic mucosal barrier in mice with chronic UC and alleviate symptoms such as diarrhea and hematochezia, which may be associated with the activation of IL-4/JAK1/STAT6 signaling pathway and the inducing of M2 macrophage polarization in colon tissue.

To observe the effect of acupuncture on the expression of brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB), extracellular signal-regulated kinase (ERK), cyclic adenosine monophosphate (cAMP) -response element binding protein (CREB), as well as synapsin1 (Syn1) and synaptophysin (Syp) in the striatum of neonatal rats with hypoxic-ischemic brain damage (HIBD), so as to explore its mechanisms underlying improvement of motor control.

Seven-day-old neonatal SD rats were randomly and equally assigned to 4 groups: blank control, sham-operation, model, and acupuncture groups (n=12 per group) according to the randomized numerical table method. The HIBD model was established by using modified Rice’s method. For rats in the acupuncture group, manual acupuncture stimulation of“ Dazhui” (GV14),“ Baihui” (GV20), “Shuigou” (GV26) and “Mingmen” (GV4) was given 24 h after modeling. In the sham operation group, only the left common carotid artery was isolated without clamping, and no intervention was given. The neonatal rats in each group were subjected to the balance beam test 28 d after modeling. After the acupuncture intervention, the striatum tissue of neonatal rats in each group was taken for observing histopathological and morphological changes after H. E. staining. The ultrastructural changes of the neurons of striatum were observed by transmission electron microscopy, and the immunoactivity of Syp was detected by immunohistochemistry, and the expression levels of BDNF, TrkB, p-ERK, p-CREB, Syn1, and Syp proteins were detected by using Western blot.

There were no significant differences between the blank control and sham operation groups in the Longa score, balance beam test score, Syp immunoactivity, and expression levels of BDNF, TrkB, p-ERK, p-CREB, Syn1 and Syp proteins. Compared with the sham operation group, the balance beam test score at 28^th day after modeling was significantly increased (P＜0.01), and the Syp immunoactivity and the expression levels of BDNF, TrkB, p-ERK, p-CREB, Syn1 and Syp proteins were considerably down-regulated (P＜0.01, P＜0.05, P＜0.001) in the model group. In contrast to the model group, the balance beam test score at 28 d after modeling was obviously decreased (P＜0.05), the immunoactivity of Syp, and the expression levels of BDNF, TrkB, p-ERK, p-CREB, Syn1 and Syp proteins were strikingly up-regulated (P＜0.05, P＜0.01) in the acupuncture group. H.E. staining showed disordered arrangement of the striatal neurons, unclear layers, reduced cell density, with vacuolization and nuclear pyknosis in some cells in the model group, which was milder in the injury severity of the striatal neurons in the acupuncture group. Ultrastructure results displayed that in the model group, the distribution density of striatum synaptosome was lower, the thickness of postsynaptic dense area and the length of active area were reduced, and the boundary became blurred. Whereas in the acupuncture group, the synaptic structure of the striatum was more regular, the distribution density of synaptosomes, the thickness of the postsynaptic dense area and the length of the active area were increased.

Manual acupuncture stimulation can improve the motor control ability in neonatal rats with HIBD, which may be achieved by up-regulating the endogenous BDNF and its receptor TrkB, activating the MAPK/ERK signaling pathway, promoting the phosphorylation of CREB, and up-regulating the expression of Syn1 and Syp proteins, thereby promoting synaptic regeneration and remodeling.