Objective:To investigate the inhibitory effect of Xiaojianzhong Granule(XJZG)on food allergy(FA)and related mecha-nisms in terms of gut microbiota,zonula occluden-1(ZO-1),and Occludin.Methods:A total of 24 specific pathogen-free female BALB/c mice were randomly divided into normal group,model group,prevention group,and treatment group,with 6 mice in each group.The mice in the prevention group were given XJZG by gavage at a standard dose of 5.85 g/kg/day from 3 days before the first challenge till 4 hours before the last challenge;the mice in the treatment group were given XJZG at the double dose for 3 days based on the allergy score;the mice in the other groups were given an equal volume of distilled water by gavage.At the end of the experiment,al-lergy score and anal temperature were measured;flow cytometry was used to measure eosinophils and mast cells in mesenteric lymph nodes(MLNs);toluidine blue staining was performed for mast cells in jejunal tissue;immunohistochemistry was used to measure the expression of ZO-1 and Occludin;16S rRNA sequencing was per-formed to analyze the microbiota in the intestinal content;high-performance liquid chromatography-mass spectrometry was used to measure the content of short-chain fatty acids(SCFAs)in jejunal lavage fluid.Results:Compared with the model group,the prevention group and the treatment group had significant reductions in al-lergy score(P=0.000,P=0.000),anal temperature(P=0.002,P=0.000),the proportion of eosinophils and mast cells in MLNs(P<0.05),and mast cell infiltration in jejunal tissue(P=0.000,P=0.000).Compared with the normal group,the model group had signifi-cant increases in the relative abundances of Erysipelaceae and Turicibacter,while the prevention group and the treatment group had disappearance of Erysipelaceae and Turicibacter and an increase in the relative abundance of Porphyromonadaceae.Compared with the normal group,the model group had a significant reduction in the content of propionate in jejunal lavage fluid(P=0.014),and compared with the model group,the prevention group had a significant increase in the content of propionate in jejunal lavage fluid(P=0.024),as well as a significant increase in the treatment group(P=0.008).In the model group,the expression of ZO-1 was downregulated(P=0.010),and the expression of Occludin was significantly downregulated(P=0.002),while the expression of ZO-1 and Occludin re-turned to normal levels in the prevention group and the treatment group(P=0.001,P=0.013;P=0.025,P=0.015).Conclusion:XJZG can change the composition and abundance of gut microbiota,increase the concentration of SCFAs,upregulate the expression of ZO-1 and Occludin,promote the repair of intestinal barrier,and inhibit food allergy.

Objective:Cerebral ischemia reperfusion injury(CIRI)can cause damage to distant organs,such as the gastrointestinal tract,through the gut-brain axis.Melatonin is known to play a neuroprotective role by activating specific receptor pathways.However,the changes of melatonin receptors in the gastrointestinal tract after brain injury and their relationship with intestinal injury are still unclear.Methods:Twenty-four male Sprague-Dawley rats were randomly di-vided into the Sham group and CIRI group.The CIRI model was prepared by Zea-Longa method.The jejunum,ileum,and colon tissues of the rats were collected 2 h after ischemia and 24 h after reperfusion.The damage of intestinal and brain tissues was observed by using 2,3,5-triphenyl tetrazolium chloride(TTC)and HE staining.The positive expres-sion of zonula occludens-1(ZO-1)and Claudin5 was observed by immunofluorescence staining.The melatonin receptor 1(MT1)and melatonin receptor 2(MT2)expression was detected by reverse transcription-quantitative polymerase chain reaction(RT-qPCR),immunofluorescence staining and Western Blot.The correlation between the melatonin receptors and intestinal tight junction proteins was analyzed by general linear regression.Results:TTC staining showed that the infarct size of rats in the CIRI group was significantly higher than that in the Sham group.HE staining showed that intestinal villi was broken and shortened,and goblet cells were reduced in the CIRI group.The results of immuno-fluorescence staining revealed that the positive expression of ZO-1 and Claudin5 in the intestinal tissues of rats in the CIRI group was significantly lower than that in the Sham group(P＜0.05).Compared with the Sham group,the RT-qPCR revealed a significantly lower expression of MT1 and MT2 mRNA in the CIRI group(P＜0.05),and the decrease in colon tissue was the most obvious.The results of immunofluorescence staining and WB also showed that the expression of MTl and MT2 in the CIRI group was significantly lower than that in the Sham group(P＜0.05).A gen-eral linear regression analysis revealed the difference in mean fluorescence intensities of MT1+and MT2+between the Sham group and the CIRI group were positively correlated with the difference of ZO-1+and Claudin5+between the two groups.Conclusion:After CIRI,the expression of both MT1 and MT2 receptors in various intestinal segments was de-creased,and the decrease in colon tissue was the most significant.It is suggested that the poor recovery of stroke may be related to the decrease of melatonin receptor.