Changes in pancreatic and ileal flora and related relationships in experimental acute pancreatitis

Abstract Background/Objectives: Gut microbiota dysbiosis is a complication of acute pancreatitis (AP). However, the composition of the pancreatic and ileal microbiota and their relationship during acute pancreatitis remain unknown. Methods: AP was induced in mice using three modeling methods, Caerulein (CAE), Caerulein+lipopolysaccharide (CAE+LPS) and L-arginine (ARG). Pancreas and ileum were collected for histological study and bacterial 16S rRNA gene sequencing to investigate the changes in the pancreatic and ileal flora under different inductions and their relationships. Blood samples were tested for amylase, lipase, and inflammatory markers, and histological investigations were done to assess pancreatic and ileal pathological damage. Results: All three modeling techniques led to inflammation and AP and ileal damage. Rarefaction and Shannon indices revealed that the pancreas and ileum of AP mice had higher levels of microbial diversity. Principal coordinate analysis (PCoA) and non-metric multidimensional scaling (NMDS) analysis showed microbial structural segregation in both the AP and control groups in the pancreas and ileum. In the three AP groups, there was microbial structural segregation between the ARG and the two CAE groups (CAE, CAE+LPS). Taxonomic analysis at the genus level showed a significant increase in the relative abundance of Muribaculaceae and a decrease in the relative abundance of Dietzia in the pancreas and ileum of AP mice. The same finding was found for linear discriminant analysis of effect size (LEfSe) at the operational taxonomic unit (OTU) level. In addition, the pancreas and ileum of both CAE groups were enriched with Roseburia, whereas the pancreas of the ARG group was enriched with Escherichia-Shigella. The abundance of Muribaculaceae and Dietzia in the pancreas is associated with that in the ileum, according to Spearman correlation analysis of the pancreatic and ileal microbiota. Conclusions: These results showed that when AP was induced, caerulein and L-arginine differentially affected the pancreatic and ileal microbiota.