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Avian pathogenic Escherichia coli (APEC) can cause serious pathological changes and inflammation in chickens. Schizandrin has anti-inflammatory activity and can prevent damage to various tissues and organs. The purpose of this study was to investigate the protective effect of schizandrin on APEC-induced lung lesions in chickens and explore the potential mechanism of schizandrin protection. The schizandrin (50, 100, and 200 mg/kg) was intragastrically administered for 3 days. APEC was administered using intraperitoneal (i.p.) injection to induce lung lesions. Then, chickens were sacrificed by CO 2 inhalation 24 h later and the lung tissues were collected for examining histopathological changes, wet/dry (W/D) ratio, myeloperoxidase (MPO) activity, malondialdehyde (MDA), levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 and activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings showed that schizandrin markedly inhibited pathological changes, pulmonary edema, MPO activity and MDA content. Moreover, schizandrin markedly reduced the levels of TNF-α, IL-1β, IL-6 and IL-8 in lung tissue. Importantly, the mechanism responsible for these effects was attributed to the inhibitory effect of schizandrin on NF-κB and MAPK signaling activation. In conclusion, our findings reveal that schizandrin displays anti-oxidant and anti-inflammatory activity against APEC-induced lung lesions in chickens, paving the way for rational use of schizandrin as a protective agent against lung-related inflammatory disease., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Canine distemper virus (CDV) can cause a highly contagious disease to canid. However, how CDV affects peripheral blood lymphocyte (PBL) remains unclear., Methods: In this study, CDV infected PBL was cultured to investigate the effect of CDV on the differentiation of lymphocytes and the mRNA expression of inflammatory cytokines in PBL., Results: The results showed that CDV changed the phenotype of lymphocytes and increased the percentage of CD4 + CD8 + T cells. To explore the effect of immune response of lymphocytes to CDV, the mRNA expression of pro- and anti-inflammatory cytokines was examined. Interleukin (IL-6, IL-12B), and tumor necrosis factor (TNF)-α mRNA expression was significantly increased at 12-48 h after CDV infection. IL-10 mRNA expression was dramatically enhanced at 12-36 h after CDV infection. However, IL-4 and transforming growth factor (TGF-β) were not response to CDV infection. These results indicated that PBL differentiated intoCD4 + CD8 + T cells and improved the inflammatory response to CDV infection., Conclusions: After CDV infection, PBL differentiated into CD4 + CD8 + T cells and initiated inflammatory response., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Canine distemper (CD) is a highly contagious disease caused by the canine distemper virus (CDV), and mortality can be as high as 100%. However, there is no specific treatment for CD. In this study, the antiviral activity of the caffeic acid against CDV was evaluated in vitro. The results showed that the IC 50 of the caffeic acid against CDV at 1 and 2 h post infection (PI) is 23.3 and 32.3 μg/mL, respectively. Consistently, at 1 and 2 h PI, the caffeic acid exhibited a reduced (23.3-57.0% and 37.2-38.1%) viral inhibitory effect in vero cells. Furthermore, the caffeic acid plus Ribavirin (RBV) has greater antiviral activity against CDV than the caffeic acid or RBV individually. In addition, the caffeic acid reduced the total viral RNA synthesis by 59-86% at 24-72 h. Therefore, our data provided the experimental evidence that the caffeic acid effectively inhibited CDV infection in vero cells, which may potentially be used to treat clinical disease associated with CDV infection., (Copyright © 2017. Published by Elsevier Ltd.)

Avian pathogenic Escherichia coli (APEC) infections are responsible for great losses in the poultry industry. Quorum sensing (QS) acts as a global regulatory system that controls genes involved in bacterial pathogenesis, metabolism and protein biosynthesis. However, whether QS of APEC is related to cell damage has not been elucidated. In the present study, we explored the correlation between the damage of chicken type II pneumocytes induced by APEC and the autoinducer-2 (AI-2) activity of APEC. The results showed that when chicken type II pneumocytes were co-cultured with 10 8  CFU/ml of APEC-O78 for 6 h, the release of LDH reached the highest level (192.5 ± 13.4 U/L) (P < 0.01), and the percentages of dead cells followed the same trend in trypan blue exclusion assay. In addition, the AI-2 activity of cell-free culture fluid (CF) reached the maximum value after 6 h co-culture with 10 8  CFU/ml of APEC-O78. At the same time, the mRNA expressions of eight virulence genes (papC, fimA, fimC, hlyE, ompA, luxS, pfs, and qseA) of 10 8  CFU/ml APEC-O78 were significantly increased compared with those of 10 7  CFU/ml, and the mRNA expressions of four virulence genes (hlyE, tsh, iss, and luxS) of 10 8  CFU/ml APEC-O78 were higher than those of 10 9  CFU/ml (p < 0.05) after incubation for 6 h. These results suggested that AI-2-mediated QS is involved in the cell damage induced by APEC-O78, indicating AI-2 may be one new potential target for preventing chicken colibacillosis., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Cinobufagin (CBG), one active ingredient isolated from Venenum Bufonis, has been demonstrated to have immunoregulatory effect. The aim of this study was to investigate whether CBG can enhance the protective efficacy of formalin-inactivated Salmonella typhimurium (FIST) in mice. ICR mice were immunized with FIST (10 6  CFU/mouse) alone or mixed with CBG (10, 20, and 40 μg) or alum (200 μg) on day 1 and day 15. Two weeks after the second immunization, serum and spleen were sampled for measuring FIST-specific antibody levels, cytokine levels, and splenocyte proliferation. The results showed that CBG enhanced FIST-specific IgG and IgG2a, the levels of interferon-gamma (IFNγ) and nitric oxide (NO), and the splenocyte proliferation response induced by concanavalin A, lipopolysaccharide, and FIST. In vivo protection studies showed that CBG significantly decreased the bacterial burdens in the spleen and prolonged the survival time of FIST-immunized mice challenged with live Salmonella typhimurium. In vivo IFNγ neutralization led to a significant reduction in FIST-specific IgG2a and IFNγ levels, and in the protective efficacy in CBG/FIST-immunized mice. In conclusion, CBG enhances the protective efficacy of formalin-inactivated Salmonella typhimurium vaccine by promoting the Th1 immune response., (Copyright © 2016 Elsevier Ltd. All rights reserved.)