Picroside II Improves Severe Acute Pancreatitis-Induced Intestinal Barrier Injury by Inactivating Oxidative and Inflammatory TLR4-Dependent PI3K/AKT/NF-κB Signaling and Improving Gut Microbiota

Abstract

Background. Picroside II exerts anti-inflammatory and antidiarrheal effects for treating the diseases associated with oxidative injury. However, its function on pancreatitis-induced intestinal barrier injury remains unclear. Hypothesis/Purpose. We hypothesized that picroside II will have protective effects against pancreatitis-induced intestinal barrier injury by affecting oxidative and inflammatory signaling (Toll-like receptor 4- (TLR4-) dependent phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and nuclear factor kappa B (NF-κB)). Study Design and Methods. A Sprague-Dawley (SD) rat model with severe acute pancreatitis (SAP) was induced via the injection of sodium taurocholate (4% wt/vol; 1 mL/kg). All rats were divided into 3 groups: sham (CG), SAP-induced intestinal barrier injury (MG), and picroside II (PG) groups. Intestinal barrier injury was assessed by scanning electron microscopy (SEM), hematoxylin and eosin staining, and pathological scores. We measured the levels of pancreatitis biomarkers (amylase and lipase), oxidative and inflammatory signaling (TLR4-dependent PI3K/AKT/NF-κB), oxidative stress marker (superoxidase dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx), and malondialdehyde), and inflammatory markers (tumor necrosis factor α (TNFα), interleukin- (IL-) 1, IL-6, and IL-10) in serum and/or gut tissues. Gut microbiota composition in feces was measured by using 16S rRNA sequencing. Results. SEM showed that intestinal barrier injury was caused with the loss of intestinal villi and mitochondria destruction, and pathological scores were increased in the MG group. The levels of amylase, lipase, malondialdehyde, TNFα, IL-1, IL-6, TLR4, PI3K, AKT, and NF-κB were increased, and the levels of SOD, GPx, CAT, and IL-10 was reduced in the MG group when compared with CG group (P<0.05). Picroside II treatment inhibited the symptoms in the MG group and showed antioxidant and anti-inflammatory activities. The serum levels of picroside II had strong correlation with the levels of inflammatory and oxidative stress biomarkers (P<0.05). Picroside II treatment increased the proportion of Lactobacillus and Prevotella and decreased the proportion of Helicobacter and Escherichia_Shigella in the model. Conclusions. Picroside II improved the SAP-induced intestinal barrier injury in the rat model by inactivating oxidant and inflammatory signaling and improving gut microbiota.