Recent studies have found gut microbiota to be closely associated with onset and perpetuation of UC. Currently, studies about gut microbiota have mainly covered samples collected from the intestinal lumen. However, the luminal flora is only part of the gut microbiota. Studies of the changes in mucosal flora under pathological conditions have been lacking. In this study, we investigated the correlation between the onset of UC and flora changes in different intestinal layers. The dextran sulfate sodium(DSS)-induced UC model was established by exposing mice to cycles of DSS. The luminal contents, an inner mucus layer, and outer mucus layer were harvested under sterile conditions. The samples were then analyzed using high-throughput sequencing of 16S rRNA V3 + V4 amplicons. The colonic microbiota composition and diversity were analyzed and compared using MetaStat, LefSe, multivariate analysis of variance, and spatial statistics. The DSS-induced UC mouse model was successfully established. The diversity of the microbiota from luminal content, the outer mucus layer, and inner mucus layer were significantly different in both control and UC model groups. The statistically different OTUs belonged to Lachnospiraceae and Ruminococcaceae families within the order Clostridiales were mainly localized to the outer mucus layer. The alterations in flora composition and diversity mainly occurred in the colonic outer mucus layer. The change of flora in the colonic mucus layers is of great significance in the understanding of common features of gut flora in IBD and the understanding of the relationship between gut flora and disease progression.

Background: Ulcerative colitis (UC) is a modern refractory disease, and its etiology has been difficult to discern. Studies have shown that UC is closely associated with the gut microbiota. Garidisan is composed of wild poppy and Artemisia frigida Willd and is commonly used for the treatment of UC in Inner Mongolia, China. In clinical settings, Garidisan has been found to treat UC effectively, with low recurrence. Previous studies have shown that Garidisan has a good therapeutic effect on mice with UC, but the therapeutic mechanism is still unclear. In this study, we investigated the regulatory effect of Garidisan on dysbiosis of the gut microbiota in a UC mouse model and explored the possible mechanism of the therapeutic effect of Garidisan on UC. Methods: The UC mouse model was established by the dextran sulfate sodium (DSS) circulating free water drinking method, and the luminal contents were sampled under sterile conditions. High-throughput sequencing of the 16S rRNA gene V3 + V4 region of the luminal contents of the control group, model group, and Garidisan group was conducted, and clustering of operational taxonomic units (OTUs) and species annotation were performed. The differences in species composition and microbial community structure between individual groups of samples were analyzed using MetaStat, LefSe, rank sum test, and Bayesian causal network analysis. Results: The UC mouse model was successfully established and the sequencing results were of adequate quality. There were significant differences in the diversity of luminal contents between the control group, model group, and Garidisan group, and the differences between groups were greater than those within any group. The therapeutic effect of Garidisan on UC is attributed to the direct effect on the Lachnospiraceae family of bacteria. Conclusion: Garidisan has a good regulatory effect on the gut microbiota, and Lachnospiraceae could be an important direct target of Garidisan for the treatment of UC.

Background: Ionocytes are rare cells in airway epithelium characterized by a high expression of CFTR. Objectives: To investigate the morphology and distribution of ionocytes and the function of CFTR in the nasal mucosal epithelium of children. Methods: The exfoliated cells of nasal mucosa from 101 children were detected using flow cytometry to analyze the number of ionocytes and CFTR and the difference of CFTR function. Nasal mucosa and polyps were collected from 10 children with CRSwNP. The RNAscope of FOXI1 and CFTR was detected in pathological paraffin sections. The expression and distribution of ionocytes and CFTR in nasal mucosa and polyp epithelium were observed. Results: In CRS patients, the number of ionocytes in the nasal epithelium was lower and the number of ionocytes that did not express CFTR was higher, and the function of CFTR was also decreased. The expression of CFTR in the nasal mucosa of CRS showed the characteristics of local dense distribution and increased as the inflammation expanded. The ionocytes were “tadpole-shaped” in the epithelium and gathered in the area of high CFTR expression, the intracellular CFTR was expanded in clusters. Ionocytes that did not express CFTR was more common in the nasal polyps. Conclusions: The number of ionocytes and the function of CFTR in nasal mucosa of CRS patients decreased. With the expansion of inflammation, CFTR and ionocytes showed more obvious dense distribution. Some ionocytes lost the expression of CFTR and did not show the "tadpole" shape, which may be related to the occurrence of polyps.