Background: At present, the treatment and prevention of Pasteurella multocida infections in pigs mainly rely on antibiotics and vaccines, but inflammatory injury cannot be eliminated. The compound 18β-glycyrrhetinic acid (GA), a pentacyclic triterpenoid extracted from Glycyrrhiza glabra L. root (liquorice) and with a chemical structure similar to that of steroidal hormones, has become a research focus because of its anti-inflammatory, antiulcer, antimicrobial, antioxidant, immunomodulatory, hepatoprotective and neuroprotective effects, but its potential for the treatment of vascular endothelial inflammatory injury by P. multocida infections has not been evaluated. This study aimed to investigate the effects and mechanisms of GA intervention in the treatment of vascular endothelial inflammatory injury by P. multocida infections. Materials and Methods: Putative targets of GA intervention in the treatment of vascular endothelial inflammatory injury by P. multocida infections were identified using network pharmacological screening and molecular docking simulation. The cell viability of PIEC cells was investigated via the CCK-8 assay. The mechanism of GA intervention in the treatment of vascular endothelial inflammatory injury by P. multocida infections were investigated using cell transfection and western blot. Results: Through network pharmacological screening and molecular docking simulation, this study found that PARP1 may be a core target for GA to exert anti-inflammatory effects. Mechanistically, GA alleviates P. multocida-induced vascular endothelial inflammation by PARP1-mediated NF-κB and HMGB1 signalling suppression. Conclusion: These findings, for the first time, demonstrate the potential therapeutic relationship among GA, PARP1 and inflammatory injury, providing a candidate drug, therapeutic targets and explanation for treating vascular endothelial inflammatory injury caused by P. multocida infection.

Glaesserella parasuis (GPS), a causative agent of Glässer’s disease, is thought to be the main fatal cause of peritonitis in swine, thus resulting in high mortality and morbidity and significant economic losses to the swine industry. However, the mechanisms of GPS infection-induced apoptosis and possible therapeutic pathway for GPS infection in peritonitis remain unclear. Baicalin has important biological functions during disease treatment, such as antiviral, bacterial inhibition, anti-apoptosis, and anti-inflammatory. However, whether baicalin has anti-apoptotic effects during the process of GPS infection in peritonitis is unclear. In the present study, the anti-apoptotic effect and mechanisms of baicalin in GPS infection-induced apoptosis were investigated in porcine peritoneal mesothelial cells (PPMC). The results showed that baicalin could inhibit the apoptosis rate occurrence of PPMC induced by GPS to various degrees and inhibit the expression of apoptosis-related genes and cleaved caspase-3. Meanwhile, baicalin significantly antagonized the expression of p-JNK, p-p38, and p-ERK induced by GPS in PPMC. These findings for the first time demonstrate that baicalin exerted the effect of antagonizing GPS induced apoptosis in PPMC by inhibiting the activation of the PKC-MAPK pathway and could be a therapeutic option in the management of GPS infection.

Streptococcus suis (S. suis) is a major swine pathogen throughout the world as well as an emerging zoonotic agent. Among the symptoms caused by S. suis, including septicemia, pneumonia, endo-carditis, arthritis, and meningitis, the latter is the most overlooked. In the present study, we explored the mechanism of action of berberine against S. suis meningitis by obtaining berberine-related action targets, porcine S. suis meningitis targets, and human S. suis meningitis targets from open databases. We constructed a protein–protein interaction (PPI) network by using the STRING database and employed Cytoscape 3.8.0 to screen for core targets. We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses through DAVID. We identified 31 potential targets of berberine, of which Toll-like receptor 4 (TLR4), fibronectin 1 (FN1), superoxide dismutase (SOD1), and catalase (CAT) were the four most critical targets. GO analysis revealed the enrichment of terms related to the response to oxidative stress and the inflammatory response. KEGG analysis revealed the enrichment of the interleukin 17 (IL-17), phosphoinositide 3-kinase (PI3K)-Akt, TLR, tumor necrosis factor (TNF), and mitogen-activated protein kinase (MAPK) signaling pathways. In addition, the admetSAR results showed that berberine can cross the blood–brain barrier. The molecular docking results indicated key binding activity between TLR4–berberine and FN1–berberine. In summary, berberine protects against Streptococcus suis meningitis by regulating inflammatory response and oxidative stress in humans and pigs. Our study updates the current knowledge of the targets of S. suis meningitis to exploit new drugs in humans and pigs, to develop environmentally friendly and antibiotic-free animal-derived food products, and to improve the farming industry and economic development.