PD-1/PD-L1 axis induced host immunosuppression via PI3K/Akt/mTOR signalling pathway in piglets infected by Glaesserella Parasuis.

Glaesserella parasuis, an important respiratory bacterial pathogen, causes Glässer's disease in piglets, with potential immunosuppression. We established a piglet infection model and explored the immunosuppression mechanism to improve our understanding of the host immune response to G. parasuis. Twenty piglets were randomly divided into two groups (n = 10). The infection group was intraperitoneally challenged with 2 × 108 CFU of G. parasuis in 2 mL TSB. The control group was intraperitoneally injected with equivalent TSB. After 72 h, the piglets were sacrificed, and spleen tissue was collected. PD-1/PD-L1 expression was determined. The splenocytes were isolated to detect CD3+ T, CD3+CD4+ T, CD3+CD8+ T and CD3-CD21+cell differentiation. Via data-independent acquisition (DIA), we compared the proteomics of healthy and infected spleen tissues. Glaesserella parasuis modified CD3+ T, CD3+CD4+ T, CD3+CD8+ T and CD3-CD21+ cell differentiation and PD-1/PD-L1 expression in the spleen. The infection group had 596 proteins with significant differences in expression, of which 301 were significantly upregulated and 295 downregulated. Differentially expressed proteins (DEPs) were mainly related to immune responses. This is the first study on PD-1/PD-L1 expression in the spleen associated with immunosuppression in a piglet model to explore the protein changes related to immune responses via DIA.

Preparing a novel baicalin-loaded microemulsion-based gel for transdermal delivery and testing its anti-gout effect.

We previously demonstrated that baicalin had efficacy against gouty arthritis (GA) by oral administration. In this paper, a novel baicalin-loaded microemulsion-based gel (B-MEG) was prepared and assessed for the transdermal delivery of baicalin against GA. The preparation method and transdermal capability of B-MEG was screened and optimized using the central composite design, Franz diffusion cell experiments, and the split-split plot design. Skin irritation tests were performed in guinea pigs. The anti-gout effects were evaluated using mice. The optimized B-MEG comprised of 50 % pH 7.4 phosphate buffered saline, 4.48 % ethyl oleate, 31.64 % tween 80, 13.88 % glycerin, 2 % borneol, 0.5 % clove oil and 0.5 % xanthan gum, with a baicalin content of (10.42 ± 0.08) mg/g and particle size of (15.71 ± 0.41) nm. After 12 h, the cumulative amount of baicalin permeated from B-MEG was (672.14 ± 44.11) µg·cm-2. No significant skin irritation was observed following B-MEG application. Compared to the model group, B-MEG groups significantly decreased the rate of auricular swelling (P < 0.01) and number of twists observed in mice (P < 0.01); and also reduced the rate of paw swelling (P < 0.01) and inflammatory cell infiltration in a mouse model of GA. In conclusion, B-MEG represents a promising transdermal carrier for baicalin delivery and can be used as a potential therapy for GA.

Baicalin and baicalein attenuate hyperuricemic nephropathy via inhibiting PI3K/AKT/NF-κB signalling pathway.

AIM: Inflammation and apoptosis are main pathological processes that lead to the development of hyperuricemic nephropathy (HN). This study aims to explore whether baicalin (BA) and baicalein (BAI) can relieve the damage through PI3K/AKT/NF-κB signal pathway and provide more reliable and precise evidence for the treatment of HN. METHODS: HN mice were induced by yeast extract with potassium oxonate (PO), and HK-2 cells were induced by monosodium urate (MSU). Molecular docking, western blot, q-PCR, and other methods were used to explore the changes of various indicators in HN mice and HK-2 cells. RESULTS: Molecular docking results showed that BA and BAI had good binding ability with PI3K, AKT, p65 and IκBα. BA and BAI significantly ameliorated the levels of renal function, decreased the p-PI3K, p-AKT and p-p65 expression, down-regulated the BAX/BCL2 and CASP3, and blunted the mRNA levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-18 in both renal tissue of HN mice and HK-2 cells induced by MSU. BA and BAI also decreased the oxidative stress level of MSU-induced HK-2 cells. CONCLUSION: BA and BAI were confirmed to attenuate HN through alleviating renal inflammatory and apoptosis in cells and tissues by inhibiting PI3K/AKT/NF-κB pathway. BA and BAI were expected to be developed as new anti-HN drugs.

Adsorption-desorption and degradation of colistin in soils under aerobic conditions.

Colistin has broad-spectrum activity against Gram-negative bacteria and has been considered as the last-resort treatment for multiantibiotic-resistant Gram-negative bacteria infections in human. And it is also world widely utilized as a veterinary medicine for the promotion of growth, prevention and control of diseases in livestock and poultry. Extensive use of colistin in husbandry results in the introduction of large amounts of colistin to the surrounding environment via animals' urine and feces, potentially inducing the prevalence of colistin resistance bacteria and the impact of the ecological environment. The study investigated the adsorption, desorption and degradation of colistin in soils using high sensitivity UPLC-MS/MS assays. An MS based assay was established to directly determine colistin in the soil. It was observed that the moderate adsorption affinity of colistin to the three soils with adsorption strength (1/n) ranging from 0.6897 to 1.3333. Colistin exhibited the highest adsorption affinity to the sandy loam, followed by the sand and loam. Despite of different characteristics of three soils, the adsorption capacity of the three soils was comparable. The adsorption of colistin to the three types of soils analyzed was irreversible. The degradation experiments showed that the degradation of colistin in the sandy loam was relatively slow with a degradation half-life in a range of 13.2-29.7 days when colistin was applied to the sandy loam at a level of 10 ~ 40 µg/g. The degradation of colistin occurred in the mixture of the sandy loam and feces recovered from the colistin treated broiler as well. 25% of colistin remained in the mixture under environmental conditions after 14 days. Composting the sandy loam by directly covering the soil surface with colistin treated broilers' feces resulted in the introduction of colistin to the sandy loam. Colistin was observed in both the topsoil from the contact surface and sandy loam samples collected 20 cm below the contact surface. The understanding of adsorption-desorption behaviors, degradation and mobility of colistin in soils might offer insights into the potential impact of colistin on the emergence and prevalence of resistant bacteria and the ecological environment.

Baicalin Alleviate Apoptosis via PKC-MAPK Pathway in Porcine Peritoneal Mesothelial Cells Induced by Glaesserella parasuis.

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.

Network pharmacology and molecular docking analysis on molecular targets: Mechanisms of baicalin and baicalein against hyperuricemic nephropathy.

Oxidative stress and inflammation in kidney are the main causes for hyperuricemic nephropathy (HN). Baicalin and baicalein, two flavonoids, have anti-inflammatory and anti-oxidative effects and they are interconvertible in the body. In this study, both baicalin and baicalein were administered by intragastric administration (i.g.) or intraperitoneal injection (i.p.) at the dose of 50 mg kg-1, once a day for 15 consecutive days to HN mice, a model established by i.g. of yeast extract combined with i.p. of potassium oxonate. In HN mice, baicalin and baicalein reduced serum uric acid (SUA) levels and protected kidneys by anti-inflammatory and anti-oxidative effects. Mechanistically, the effect of baicalin and baicalein on reducing SUA levels might due to their inhibitory effect on xanthine oxidase (XO) activity in vivo and in vitro. Furthermore, the mechanisms of baicalin and baicalein against HN were analyzed with network pharmacology and molecular docking technology. The network pharmacology indicated that the protective effects of baicalin and baicalein against HN were mainly related to their down-regulating effects on TLRs, NF-κB, MAPK, PI3K/AKT and NOD-like receptor signaling pathways. Molecular docking indicated high binding affinity of baicalin/baicalein to targets such as AKT1 and MAPK1. In summary, baicalin and baicalein are promising drug candidates for the treatment of HN by inhibiting XO activity, reducing inflammation and cell apoptosis through down-regulating TLRs/NLRP3/NF-κB, MAPK, PI3K/AKT/NF-κB pathways.

Protective Effects of Baicalin on Peritoneal Tight Junctions in Piglets Challenged with Glaesserella parasuis.

Glaesserella parasuis (G. parasuis) causes inflammation and damage to piglets. Whether polyserositis caused by G. parasuis is due to tight junctions damage and the protective effect of baicalin on it have not been examined. Therefore, this study aims to investigate the effects of baicalin on peritoneal tight junctions of piglets challenged with G. parasuis and its underlying molecular mechanisms. Piglets were challenged with G. parasuis and treated with or without baicalin. RT-PCR was performed to examine the expression of peritoneal tight junctions genes. Immunofluorescence was carried out to detect the distribution patterns of tight junctions proteins. Western blot assays were carried out to determine the involved signaling pathways. Our data showed that G. parasuis infection can down-regulate the tight junctions expression and disrupt the distribution of tight junctions proteins. Baicalin can alleviate the down-regulation of tight junctions mRNA in peritoneum, prevent the abnormalities and maintain the continuous organization of tight junctions. Our results provide novel evidence to support that baicalin has the capacity to protect peritoneal tight junctions from G. parasuis-induced inflammation. The protective mechanisms of baicalin could be associated with inhibition of the activation of PKC and MLCK/MLC signaling pathway. Taken together, these data demonstrated that baicalin is a promising natural agent for the prevention and treatment of G. parasuis infection.

The effect of baicalin on microRNA expression profiles in porcine aortic vascular endothelial cells infected by Haemophilus parasuis.

Glässer's disease, caused by Haemophilus parasuis (H. parasuis), is associated with vascular damage and vascular inflammation in pigs. Therefore, early assessment and treatment are essential to control the inflammatory disorder. MicroRNAs have been shown to be involved in the vascular pathology. Baicalin has important pharmacological functions, including anti-inflammatory, antimicrobial and antioxidant effects. In this study, we investigated the changes of microRNAs in porcine aortic vascular endothelial cells (PAVECs) induced by H. parasuis and the effect of baicalin in this model by utilizing high-throughput sequencing. The results showed that 155 novel microRNAs and 76 differentially expressed microRNAs were identified in all samples. Subsequently, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the target genes of the differentially expressed microRNAs demonstrated that regulation of actin cytoskeleton, focal adhesion, ECM-receptor interaction, bacterial invasion of epithelial cells, and adherens junction were the most interesting pathways after PAVECs were infected with H. parasuis. In addition, when the PAVECs were pretreated with baicalin, mismatch repair, peroxisome, oxidative phosphorylation, DNA replication, and ABC transporters were the most predominant signaling pathways. STRING analysis showed that most of the target genes of the differentially expressed microRNAs were associated with each other. The expression levels of the differentially expressed microRNAs were negatively co-regulated with their target genes' mRNA following pretreatment with baicalin in the H. parasuis-induced PAVECs using co-expression networks analysis. This is the first report that microRNAs might have key roles in inflammatory damage of vascular tissue during H. parasuis infection. Baicalin regulated the microRNAs changes in the PAVECs following H. parasuis infection, which may represent useful novel targets to prevent or treat H. parasuis infection.

The effects of baicalin on piglets challenged with Glaesserella parasuis.

Glaesserella parasuis (G. parasuis) causes porcine vascular inflammation and damage. Baicalin is reported to have antioxidant and anti-inflammatory functions. However, whether baicalin protects piglets against G. parasuis challenge and the potential protective mechanism have not been investigated. Therefore, in this study, we comprehensively examined the protective efficacy of baicalin in piglets challenged with G. parasuis and the possible protective mechanism. Our results show that baicalin attenuated the release of the inflammation-related cytokines interleukin (IL) 1ß, IL6, IL8, IL10, and tumour necrosis factor α (TNF-α) and reduced high mobility group box 1 (HMGB1) production and cell apoptosis in piglets infected with G. parasuis. Baicalin also inhibited the activation of the mitogen-activated protein kinase (MAPK) signalling pathway and protected piglets against G. parasuis challenge. Taken together, our data suggest that baicalin could protect piglets from G. parasuis by reducing HMGB1 release, attenuating cell apoptosis, and inhibiting MAPK signalling activation, thereby alleviating the inflammatory response induced by the bacteria. Our results suggest that baicalin has utility as a novel therapeutic drug to control G. parasuis infection.

Effects of Baicalin on piglet monocytes involving PKC-MAPK signaling pathways induced by Haemophilus parasuis.

BACKGROUND: Haemophilus parasuis (HPS) is the causative agent of Glässer's disease, characterized by arthritis, fibrinous polyserositis and meningitis, and resulting in worldwide economic losses in the swine industry. Baicalin (BA), a commonly used traditional Chinese medication, has been shown to possess a series of activities, such as anti-bacterial, anti-viral, anti-tumor, anti-oxidant and anti-inflammatory activities. However, whether BA has anti-apoptotic effects following HPS infection is unclear. Here, we investigated the anti-apoptotic effects and mechanisms of BA in HPS-induced apoptosis via the protein kinase C (PKC)-mitogen-activated protein kinase (MAPK) pathway in piglet's mononuclear phagocytes (PMNP). RESULTS: Our data demonstrated that HPS could induce reactive oxygen species (ROS) production, arrest the cell cycle and promote apoptosis via the PKC-MAPK signaling pathway in PMNP. Moreover, when BA was administered, we observed a reduction in ROS production, suppression of cleavage of caspase-3 in inducing apoptosis, and inhibition of activation of the PKC-MAPK signaling pathway for down-regulating p-JNK, p-p38, p-ERK, p-PKC-α and PKC-δ in PMNP triggered by HPS. CONCLUSIONS: Our data strongly suggest that BA can reverse the apoptosis initiated by HPS through regulating the PKC-MAPK signaling pathway, which represents a promising therapeutic agent in the treatment of HPS infection.

Pharmacokinetics of sodium baicalin following intravenous and intramuscular administration to piglets.

The purpose of this study was to determine the pharmacokinetics of baicalin after intravenous and intramuscular administration of sodium baicalin at 50 mg/kg to piglets. Plasma baicalin levels were determined by high-performance liquid chromatography. The plasma concentration-time data of baicalin for both administration routes were best described by two-compartmental open model. The area under the plasma concentration-time curve and the elimination half-lives were 77.47 ± 6.14 µg/ml × h and 1.73 ± 0.16 hr for intravenous and 64.85 ± 5.67 µg/ml × h and 2.42 ± 0.15 hr for intramuscular administration, respectively. The apparent volume of distribution and body clearance were 1.63 ± 0.23 L/kg and 2.74 ± 0.30 L h-1  kg-1 for intravenous and 0.51 ± 0.10 L/kg and 0.78 ± 0.08 L h-1  kg-1 for intramuscular routes, respectively. An intramuscular injection of sodium baicalin in piglets resulted in rapid and complete absorption, with a mean maximal plasma concentration of 77.28 ± 7.40 µg/ml at 0.17 hr and a high absolute bioavailability of 83.73 ± 5.53%.

Tilmicosin enteric granules and premix to pigs: Antimicrobial susceptibility testing and comparative pharmacokinetics.

The purpose of this study was to compare the pharmacokinetics and relative bioavailability of tilmicosin enteric granules and premix after oral administration at a dose of 40 mg/kg in pigs. Three kinds of different respiratory pathogens were selected for determination of minimal inhibitory concentration (MIC) to tilmicosin. Eight healthy pigs were assigned to a two-period, randomized crossover design. A modified rapid, sensitive HPLC method was used for determining the concentrations of tilmicosin in plasma. Pharmacokinetic parameters were calculated by using WinNonlin 5.2 software. The MIC90 of tilmicosin against Haemophilus parasuis, Actinbacillus pleuropneumoniae, and Pasteurella multocida were all 8 µg/ml. These results indicated that these common pig respiratory bacteria are sensitive to tilmicosin. The main parameters of time to reach maximum plasma concentration (Tmax ), elimination half-life (t1/2ß ), mean residence time (MRT), and apparent volume of distribution (VF ) were 2.03 ± 0.37 hr, 29.31 ± 5.56 hr, 25.22 ± 2.57 hr, 4.06 ± 1.04 L/kg, and 3.05 ± 0.08 hr, 17.06 ± 1.77 hr, 15.55 ± 1.37 hr, 2.95 ± 0.62 L/kg after the orally administrated tilmicosin enteric granules and premix. The relative bioavailability of tilmicosin enteric granules to premix was 114.97 ± 7.19%, according to the AUC0-t values. These results demonstrated that tilmicosin enteric granules produced faster tilmicosin absorption, slower elimination, larger tissue distribution, and higher bioavailability compared to the tilmicosin premix. The present study results manifest that tilmicosin enteric granules can be used as a therapeutic alternative to premix in clinical treatment.

2,4-Dinitrotoluene (DNT) Perturbs Yolk Absorption, Liver Development and Lipid Metabolism/Oxygen Transport Gene Expression in Zebrafish Embryos and Larvae.

2,4-dinitrotoluene (2,4-DNT) is a common environmental pollutant, and was classified as a group 2B human carcinogenic compound by the International Agency for Research on Cancer. This study determined the toxic effects of 2,4-DNT exposure on zebrafish at the embryo-larvae stage, in terms of organ morphogenesis and the expression pattern of selected target genes related to lipid metabolism and oxygen transportation. The results showed that the 120-h post-fertilization LC50 of 2,4-DNT was 9.59 mg/L with a 95% confidence interval of 8.89-10.44 mg/L. The larvae treated with 2,4-DNT showed toxic symptoms including smaller body, less skin pigment production, yolk malabsorption, and disordered liver development. Further studies on the expression of genes related to lipid transport and metabolism, and respiration indicated that they were significantly affected by 2,4-DNT. It is concluded that 2,4-DNT exposure perturbed liver development and yolk absorption in early-life zebrafish, and disturbed the lipid metabolism /oxygen transport gene expression.

Effect of Baicalin-Aluminum Complexes on Fecal Microbiome in Piglets.

The gut microbiome has important effects on gastrointestinal diseases. Diarrhea attenuation functions of baicalin (BA) is not clear. Baicalin-aluminum complexes (BBA) were synthesized from BA, but the BBA's efficacy on the diarrhea of piglets and the gut microbiomes have not been explored and the mechanism remains unclear. This study has explored whether BBA could modulate the composition of the gut microbiomes of piglets during diarrhea. The results showed that the diarrhea rate reduced significantly after treatment with BBA. BBA altered the overall structure of the gut microbiomes. In addition, the Gene Ontology (GO) enrichment analysis indicated that the functional differentially expressed genes, which were involved in the top 30 GO enrichments, were associated with hydrogenase (acceptor) activity, nicotinamide-nucleotide adenylyltransferase activity, and isocitrate lyase activity, belong to the molecular function. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that flagellar assembly, bacterial chemotaxis, lipopolysaccharide biosynthesis, ATP-binding cassette transporters (ABC) transporters, biosynthesis of amino acids, and phosphotransferase system (PTS) were the most enriched during BBA treatment process. Taken together, our results first demonstrated that BBA treatment could modulate the gut microbiomes composition of piglets with diarrhea, which may provide new potential insights on the mechanisms of gut microbiomes associated underlying the antimicrobial efficacy of BBA.

Baicalin Inhibits Haemophilus Parasuis-Induced High-Mobility Group Box 1 Release during Inflammation.

Haemophilus parasuis (H. parasuis) can cause Glässer’s disease in pigs. However, the molecular mechanism of the inflammation response induced by H. parasuis remains unclear. The high-mobility group box 1 (HMGB1) protein is related to the pathogenesis of various infectious pathogens, but little is known about whether H. parasuis can induce the release of HMGB1 in piglet peripheral blood monocytes. Baicalin displays important anti-inflammatory and anti-microbial activities. In the present study, we investigated whether H. parasuis can trigger the secretion of HMGB1 in piglet peripheral blood monocytes and the anti-inflammatory effect of baicalin on the production of HMGB1 in peripheral blood monocytes induced by H. parasuis during the inflammation response. In addition, host cell responses stimulated by H. parasuis were determined with RNA-Seq. The RNA-Seq results showed that H. parasuis infection provokes the expression of cytokines and the activation of numerous pathways. In addition, baicalin significantly reduced the release of HMGB1 in peripheral blood monocytes induced by H. parasuis. Taken together, our study showed that H. parasuis can induce the release of HMGB1 and baicalin can inhibit HMGB1 secretion in an H. parasuis-induced peripheral blood monocytes model, which may provide a new strategy for preventing the inflammatory disorders induced by H. parasuis.

Transcriptional Profiling of Host Cell Responses to Virulent Haemophilus parasuis: New Insights into Pathogenesis.

Haemophilus parasuis is the causative agent of Glässer’s disease in pigs. H. parasuis can cause vascular damage, although the mechanism remains unclear. In this study, we investigated the host cell responses involved in the molecular pathway interactions in porcine aortic vascular endothelial cells (PAVECs) induced by H. parasuis using RNA-Seq. The transcriptome results showed that when PAVECs were infected with H. parasuis for 24 h, 281 differentially expressed genes (DEGs) were identified; of which, 236 were upregulated and 45 downregulated. The 281 DEGs were involved in 136 KEGG signaling pathways that were organismal systems, environmental information processing, metabolism, cellular processes, and genetic information processing. The main pathways were the Rap1, FoxO, and PI3K/Akt signaling pathways, and the overexpressed genes were determined and verified by quantitative reverse transcription polymerase chain reaction. In addition, 252 genes were clustered into biological processes, molecular processes, and cellular components. Our study provides new insights for understanding the interaction between bacterial and host cells, and analyzed, in detail, the possible mechanisms that lead to vascular damage induced by H. parasuis. This may lead to development of novel therapeutic targets to control H. parasuis infection.

Roles of amino acids in preventing and treating intestinal diseases: recent studies with pig models.

Animal models are needed to study and understand a human complex disease. Because of their similarities in anatomy, structure, physiology, and pathophysiology, the pig has proven its usefulness in studying human gastrointestinal diseases, such as inflammatory bowel disease, ischemia/reperfusion injury, diarrhea, and cancer. To understand the pathogenesis of these diseases, a number of experimental models generated in pigs are available, for example, through surgical manipulation, chemical induction, microbial infection, and genetic engineering. Our interests have been using amino acids as therapeutics in pig and human disease models. Amino acids not only play an important role in protein biosynthesis, but also exert significant physiological effects in regulating immunity, anti-oxidation, redox regulation, energy metabolism, signal transduction, and animal behavior. Recent studies in pigs have shown that specific dietary amino acids can improve intestinal integrity and function under normal and pathological conditions that protect the host from different diseases. In this review, we summarize several pig models in intestinal diseases and how amino acids can be used as therapeutics in treating pig and human diseases.

Evaluation of recombinant protein superoxide dismutase of Haemophilus parasuis strain SH0165 as vaccine candidate in a mouse model.

Haemophilus parasuis can cause a severe membrane inflammation disorder. It has been documented that superoxide dismutase (SOD) is a potential target to treat systemic inflammatory diseases. Therefore, we constructed an experimental H. parasuis subunit vaccine SOD and determined the protective efficacy of SOD using a lethal dose challenge against H. parasuis serovar 4 strain MD0322 and serovar 5 strain SH0165 in a mouse model. The results demonstrated that SOD could induce a strong humoral immune response in mice and provide significant immunoprotection efficacy against a lethal dose of H. parasuis serovar 4 strain MD0322 or serovar 5 strain SH0165 challenge. IgG subtype analysis indicated SOD protein could trigger a bias toward a Th1-type immune response and induce the proliferation of splenocytes and secretion of IL-2 and IFN-γ of splenocytes. In addition, serum in mice from the SOD-immunized group could inhibit the growth of strain MD0322 and strain SH0165 in the whole-blood killing bacteria assay. This is the first report that immunization of mice with SOD protein could provide protective effect against a lethal dose of H. parasuis serovar 4 and serovar 5 challenge in mice, which may provide a novel approach against heterogeneous serovar infection of H. parasuis in future.

Baicalin suppresses NLRP3 inflammasome and nuclear factor-kappa B (NF-κB) signaling during Haemophilus parasuis infection.

Haemophilus parasuis (H. parasuis) is the causative agent of Glässer's disease, a severe membrane inflammation disorder. Previously we showed that Baicalin (BA) possesses anti-inflammatory effects via the NLRP3 inflammatory pathway in an LPS-challenged piglet model. However, whether BA has anti-inflammatory effects upon H. parasuis infection is still unclear. This study investigated the anti-inflammatory effects and mechanisms of BA on H. parasuis-induced inflammatory responses via the NF-κB and NLRP3 inflammasome pathway in piglet mononuclear phagocytes (PMNP). Our data demonstrate that PMNP, when infected with H. parasuis, induced ROS (reactive oxygen species) production, promoted apoptosis, and initiated transcription expression of IL-6, IL-8, IL-10, PGE2, COX-2 and TNF-α via the NF-κB signaling pathway, and IL-1ß and IL-18 via the NLRP3 inflammasome signaling pathway. Moreover, when BA was administrated, we observed a reduction in ROS production, suppression of apoptosis, and inhibition of the activation of NF-κB and NLRP3 inflammasome signaling pathway in PMNP treated with H. parasuis. To our best knowledge, this is the first example that uses piglet primary immune cells for an H. parasuis infection study. Our data strongly suggest that BA can reverse the inflammatory effect initiated by H. parasuis and possesses significant immunosuppression activity, which represents a promising therapeutic agent in the treatment of H. parasuis infection.

Baicalin attenuates aflatoxin B1-induced hepatotoxicity via suppressing c-Jun-N-terminal kinase-mediated cell apoptosis.

Aflatoxin B1 (AFB1) is classified as a Class I carcinogen and common pollutant in human and animal food products. Prolonged exposure to AFB1 can induce hepatocyte apoptosis and lead to hepatotoxicity. Therefore, preventing AFB1-induced hepatotoxicity remains a critical issue and is of great significance. Baicalin, a polyphenolic compound derived from Scutellaria baicalensis Georgi, has a variety of pharmacodynamic activities, such as antiapoptotic and anticancer activities. This study systematically investigated the alleviating effect of baicalin on AFB1-induced hepatotoxicity from the perspective of apoptosis and explored the possible molecular mechanism. In the normal human liver cell line L02, baicalin treatment significantly inhibited AFB1-induced c-Jun-N-terminal Kinase (JNK) activation and cell apoptosis. In addition, the in vitro mechanism study demonstrated that baicalin alleviates AFB1-induced hepatocyte apoptosis through suppressing the translocation of phosphorylated JNK to the nucleus and decreasing the phosphorylated c-Jun/c-Jun ratio and the Bax/Bcl2 ratio. Molecular docking and drug affinity responsive target stability assays demonstrated that baicalin has the potential to target JNK. This study provides a basis for the therapeutic effect of baicalin on hepatocyte apoptosis caused by AFB1, indicating that the development of baicalin and JNK pathway inhibitors has broad application prospects in the prevention of hepatotoxicity, especially hepatocyte apoptosis.