Studies have shown that Periplaneta americana extract (PAE) has good therapeutic effects in inflammatory disorders such as ulcerative colitis, alcoholic hepatitis, and gastric ulcers. However, whether or not PAE has good pre-protective effects has not been widely and deeply studied. In this study, we investigated the effects of PAE pretreatment for 7 days on oxidative stress and inflammation triggered by oxidative stress by using diquat-induced C57BL/6 mice as an oxidative stress model. The results showed that PAE pretreatment could significantly reduce oxidative stress in the intestine and liver by reducing the production of MDA, and improved antioxidant systems (SOD, CAT, GSH, and T-AOC). By primarily activating the anti-inflammatory cytokine (IL-10) mediated JAK1/STAT3 signaling pathway, PAE also effectively reduced oxidative stress-induced liver inflammation while also reducing liver damage, as evidenced by the reductions in serum AST and ALT. PAE pretreatment also had a significant effect on maintaining the intestinal barrier function, which was manifested by inhibiting a decrease in the expression of tight junction proteins (ZO-1 and occludin), and reducing the increased intestinal permeability (serum DAO and D-Lac) caused by diquat. The 16S rRNA sequencing analysis revealed that diquat decreased the gut microbiota diversity index and increased the abundance of pathogenic bacteria (e.g. Allobaculum, Providenci,a and Escherichia-Shigella), while PAE pretreatment responded to diquat-induced damage by greatly increasing the abundance of Akkermansia muciniphila. These findings elucidate potential pre-protective mechanisms of PAE in alleviating oxidative stress and inflammation, while providing a direction for the treatment of metabolic diseases by utilizing PAE to enhance the abundance of gut A. muciniphila.

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Background: Hyperosmotic stress resulting from lumen contents is a big challenge to the normal function of the intestinal epithelium. Betaine is a potent organic osmolyte, but it is mostly studied in kidney. The purpose of this study was to gain insight into the osmoprotectant role of betaine in intestinal epithelium of piglets and intestinal porcine epithelial cells (IPEC-J2 cells) under hyperosmotic condition.Results: The result showed that the osmolarity of intestinal chyme was much higher than that of plasma (P < 0.05), indicating a natural hyperosmotic environment of intestinal lumen and subsequently leading to hyperosmotic stress to intestinal epithelium. Meanwhile, hyperosmolarity corresponding to intestinal environment was simulated by 150 mmol/L NaCl in vitro and caused a significant decrease of cell viability (P < 0.05). It was found that betaine could remarkably decrease hyperosmolarity-induced reactive oxygen species (ROS) of intestinal epithelium in vivo and vitro (P < 0.05) with the significant restoration of cell shrinkage (P < 0.05). Furthermore, since hyperosmolarity caused mitochondrial-related apoptosis with the remarkable increase of cleaved Caspase3, cleaved PARP-1, cytoplasm cytochrome c as well as obvious decrease of Bcl-2 in protein level (P < 0.05), betaine prevented mitochondria from membrane collapse and alleviated apoptosis (P < 0.05) in vivo and vitro. Meanwhile, it was also confirmed that betaine reduced hyperosmotic stress-induced apoptotic incidence in IPEC-J2 cells via fluorescence microscope and flow cytometry (P < 0.05). In addition, betaine supplementation significantly suppressed hyperosmotic stress-induced elevated expression of LC3 II and reduced expression of p62 (P < 0.05). indicating that betaine ameliorated autophagy of porcine intestinal epithelium caused by hyperosmolarity in vivo and vitro. Autophagic flux determined by mRFP-GFP-LC3B system in IPEC-J2 cells was in agreement with the result of western blotting as well (P < 0.05). Conclusions: Betaine could alleviate hyperosmotic stress-induced cell shrinkage, ROS accumulation as well as ameliorate subsequently apoptosis and autophagy in small intestinal epithelium of piglets and IPEC-J2 cells.