[Mechanism of electroacupuncture at "Tianshu" (ST25) and "Dachangshu" (BL25) for attenuating visceral...

To investigate the mechanism of electroacupuncture (EA) for attenuating visceral hypersensitivity in rats with post-inflammatory irritable bowel syndrome (PI-IBS) using transcriptome sequencing technology.

Of 40 SPF grade male Wistar rats, 12 rats were randomly selected as the control group. Enema of 2,4,6-trinitrobenzenesulfonic acid solution (TNBS) was adopted to prepare PI-IBS models among the remaining 28 rats. The successfully-modeled 24 rats were randomized into a model group and an EA group, 12 rats in each one. In the EA group, EA was delivered at bilateral"Tianshu" (ST25) and "Dachangshu" (BL25), with disperse-dense wave, at a frequency of 2 Hz/100 Hz and an electric current of 1 mA, for 20 min, once daily, and EA intervention was composed of 10 days. Visceral sensitivity was detected by the abdominal withdrawal reflex (AWR) method, and the area under the curve (AUC) of rectus abdominis electromyography(EMG) was measured under different pressures of colonic dilation. HE staining was used to observe colonic mucosal morphology and pathological score was calculated; transcriptome sequencing was applied to detect differentially expressed genes (DEGs) in the colon; and real-time fluorescent quantitative PCR was used to detect the mRNA expression of DEGs.

Compared with the control group, AWR scores and AUC under each pressure increased in the model group (P<0.001, P<0.01). Compared with the model group, EA group showed the decrease in AWR scores and AUC under each pressure (P<0.001, P<0.01). The model group exhibited the damaged colonic mucosal integrity, accompanied by mild congestion, edema, and a small amount of inflammatory cell infiltration, while the EA group showed the alleviation in colonic mucosal lesions. Regarding DEGs, there were 141 reversed genes in the EA group. When compared with the control group,DEGs in the model group were mainly enriched in cytokine-cytokine receptor interaction, chemokine signaling pathway and P53 signaling pathway, etc. DEGs in the EA group were mainly enriched in peroxisome proliferator-activated receptor signaling pathway, biosynthesis of amino acid, and P53 signaling pathway in comparison with the model group. The top 5 core DEGs reversed by EA were CXC chemokine ligand 10 (CXCL10), chemokine ligand 20 (CCL20), CXC chemokine receptor 4(CXCR4), chemokine ligand 21 (CCL21), and CXC chemokine receptor 5 (CXCR5). Compared with the control group, the mRNA expression of CXCL10 and CCL20 of the colon was elevated (P<0.001 ), and that of CXCR4 reduced (P<0.01) in the model group. When compared with the model group, EA group showed the decrease in the mRNA expression of CXCL10 and CCL20 of the colon (P<0.01, P<0.001), and the increase in that of CXCR4 (P<0.001).

Electroacupuncture at "Tianshu" (ST25) and "Dachangshu" (BL25) can attenuate visceral hypersensitivity in PI-IBS rats, probably by regulating the expression of genes such as CXCL10, CCL20, CXCR4.