Gut microbiota plays an important role in the maintenance of physiological function and genesis of some gut diseases. Brain-gut axis,as an important link between brain and gastrointestinal tract,is a requisite of gut microbiota stability. The dysfunction of brain-gut axis may lead to intestinal dysbiosis through activation of intestinal immune activity. Conversely,intestinal dysbiosis can influence nervous system development and may cause dysfunction of brain-gut axis,in which vagus nerve and metabolites in serum may be the critical factors. This article reviewed the advances in study on interaction between gut microbiota and brain-gut axis.

Objective:To explore the effect of inherent depression on chronic visceral hypersensitivity. The differences of visceral sensitivity, colitis, and brain activation between Fawn-Hooded ( FH/Wjd) and Sprague-Dawley( SD) rats were identified after neonatal colon acetate stimulation.Methods:The specific pathogen free Fawn-Hooded (FH/Wjd) and Sprague-Dawley(SD) rats were used to establish irritable bowel syndrome (IBS) model.The visceral sensitivity was measured by colorectal distension (CRD). The expression of 5-hydroxytryptamine (5-HT), mast cell (MC), indoleamine 2,3-dioxygenase (IDO) in colon and IDO in specific cerebral regions were detected through immunohistochemistry.Results:Ab-dominal withdrawal reflex ( AWR) scores showed that visceral sensitivity of acetate-enema groups was sig-nificantly higher than that of saline-enema groups ( FH/Wjd:2.44 ±0.04 vs.1.96 ±0.07, P<0.05;SD:1.75 ±0.13 vs.1.32 ±0.05, P<0.05).Furthermore, FH/Wjd rats of IBS group scored signifi-cantly higher than SD rats of IBS group (2.44 ±0.04 vs.1.75 ±0.13, P<0.05).The MC amounts of both SD and FH/Wjd IBS group rats were significantly more than those of their control groups ( FH/Wjd:43.24 ±1.72 vs.24.92 ±1.38, P <0.01.SD:23.80 ±1.28 vs.14.24 ±0.92, P <0.01).
Besides, the MC amounts of control and IBS group of FH/Wjd rats were significantly more than that of SD IBS group rats ( P<0 .01 ) .The IDO and 5-HT positive cells in colonic mucosa of IBS group of both SD and FH/Wjd rats were significantly more than those of their control groups, respectively(P <0.01). The IDO, 5-HT positive cells in colonic mucosa of both control and IBS group of FH/Wjd rats were significantly more than those of both control and IBS group of SD rats ( control:IDO,24.64 ±2.22 vs. 15.52 ±1.39;5-HT,21.32 ±1.26 vs.12.72 ±1.12.IBS: IDO,44.92 ±2.31 vs.20.85 ±1.72;5-HT, 31.84 ±1.57 vs.19.65 ±1.09.P <0.01).The expression of IDO in prelimbic cortex (PrL) areas of FH/Wjd IBS rats was significantly higher than that of IBS group of SD rats (49.60 ±4.31 vs. 35.60 ±2.42, P <0.01) , and the expression of IDO in rostral anterior cingulate cortex ( rACC) areas of FH/Wjd IBS rats was significantly more than that of FH/Wjd control rats (45.44 ±1.16 vs.34.08 ± 2.76, P <0.01) .Conclusion:Inherent depressive FH/Wjd rats were more sensitive to neonatal colon acetate stimulation, presenting as visceral hypersensitivity which maybe associated with increased MC amounts and over-expression of 5-HT and IDO in colon, suggesting that depression disorder may aggra-vate functional disturbance of gastrointestinal tract by regulating the response to inflammatory stimulation.

Objective To estimate the prevalence and risk factors for irritable bowel syndrome (IBS) in China.Methods Cross-sectional studies relevant to IBS conducted among Chinese were identified through the databases including PubMed,Web of Science,the Cochrane Library,CBM,CNKI,Wanfang data and VIP.Quality of studies was assessed according to the criteria for cross-sectional studies recommended by Agency for Healthcare Research and Quality(AHRQ).Analysis of data,publication bias and sensitivity were performed with Stata (Version 12.0).Results A total of twenty-three studies were extracted.No obvious publication bias was detected in all analysis except the effect of depression on IBS prevalence.Pooled prevalence of IBS in China was 6.5％.IBS was more common in women than in men (8.1％ vs 6.8％;OR=1.23,95％CI 1.09-1.38) and high rate in age group between 30 to 59 years (6.9％ ; OR =1.22,95％ CI 1.12-1.32).Intestinal infection history(OR =2.39,95％ CI 1.69-3.38),anxiety (OR =2.95,95 ％ CI 1.94-4.49),depression (OR =1.85,95 ％ CI 1.11-3.09),food allergy (OR =2.80,95％ CI 2.12-3.67) and alcohol consumption (OR =1.15,95％ CI 1.07-1.24) might increase the risk for IBS.There were no significant difference of IBS prevalence between urban and rural areas (OR =0.97,95％ CI 0.72-1.29),neither in different education classes (OR =0.85,95％ CI 0.70-1.03).Sub-group analysis showed IBS prevalence varied apparently with different diagnostic criteria:prevalence defined by Manning was 11.8％ and by Rome Ⅱ and Rome Ⅲ prevalence values were 4.4％ and 8.9％ respectively.Conclusions Pooled prevalence of IBS in China was 6.5％.IBS is more common in age group between 30 to 59 years.Female,history of intestinal infection,anxiety,depression,food allergy and alcohol consumption were risk factors for IBS in Chinese population.

Objective To observe the effect of heat needle treatment on the inflammatory reaction in the damaged tissues of rats with the third lumbar transverse process syndrome. Methods Ninety Sprague-Dawley rats were randomly divided into 6 groups, namely normal group, model group, drug group, heat needle group, conventional acupuncture group and warming acup-moxibustion group, 15 rats in each group. The rat model of the third lumbar syndrome was established by embedding gelatin sponge. Two weeks later, the rats in various groups were given corresponding treatment respectively. Before treatment and on the 7th, 14th and 28th day of treatment, the blood samples were collected from jugular vein, and then the serum inflammatory cytokines of tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β and IL-6 were detected by enzyme-linked immunosorbent assay (ELISA). On the 28th day of treatment, all of the rats were sacrificed, the expression levels of TNF-α, IL-1βand IL-6 mRNA in the muscle tissue were detected by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), and the pathological changes in local muscle tissue were observed by HE staining method. Results The serum contents of the inflammatory cytokines of TNF-α, IL-1β and IL-6 in the model group and treatment groups after modeling were significantly higher than those in the normal group (P < 0.05). After treatment, the contents of TNF-α, IL-1β and IL-6 in various treatment groups were decreased significantly as compared with those in the model group, and the decrease was most obvious in the heat needle group. The expression levels of TNF-α, IL-1β and IL-6 mRNA in muscle tissues of drug group, heat needle group, conventional acupuncture group and warming acup-moxibustion group were lower than those of the model group (P < 0.05), and the heat needle group had the lowest levels. HE staining results showed that heat needle group had milder inflammatory reaction and better muscle fiber structure than the model group. Conclusion Heat needle treatment can improve the local inflammatory response and promote the repair of tissue damage through decreasing the expression levels of inflammatory cytokines of TNF-α, IL-1βand IL-6.