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Glaesserella parasuis (G. parasuis) induces vascular damage and systemic inflammation. However, the mechanism by which it causes vascular damage is currently unclear. Baicalin has important anti-inflammatory, antibacterial and immunomodulatory functions. In this study, we explored the ability of baicalin and probenecid to protect against G. parasuis challenge in a piglet model. Sixty piglets were randomly divided into a control group; an infection group; a probenecid group; and 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups. The probenecid group and the 25 mg/kg, 50 mg/kg and 100 mg/kg baicalin groups were injected intramuscularly with 20 mg/kg body weight (BW) probenecid and 25 mg/kg BW, 50 mg/kg BW and 100 mg/kg BW baicalin, respectively. All piglets except those from the control group were injected intraperitoneally with 1 × 108 CFU of G. parasuis. The control group was injected intraperitoneally with TSB. The results showed baicalin and probenecid protected piglets against G. parasuis challenge, improved body weight and decreased temperature changes in piglets. Baicalin and probenecid attenuated IL-1ß, IL-10, IL-18, TNF-α and IFN-γ mRNA levels in the blood for 48 h, inhibited the production of the nucleosides ATP, ADP, AMP and UMP from 24 to 72 h, reduced Panx-1/P2Y6/P2X7 expression, weakened NF-kB, AP-1, NLRP3/Caspase-1 and ROCK/MLCK/MLC signalling activation, and upregulated VE-cadherin expression in the blood vessels of piglets challenged with G. parasuis. Baicalin and probenecid alleviated pathological tissue damage in piglets induced by G. parasuis. Our results might provide a promising strategy to control and treat G. parasuis infection in the clinical setting.
Assuntos
Flavonoides , Haemophilus parasuis , Probenecid , Doenças dos Suínos , Animais , Probenecid/farmacologia , Flavonoides/farmacologia , Flavonoides/administração & dosagem , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/prevenção & controle , Haemophilus parasuis/efeitos dos fármacos , Infecções por Haemophilus/veterinária , Infecções por Haemophilus/prevenção & controleRESUMO
Infection of piglets with Glaesserella parasuis (G. parasuis) induces host immunosuppression. However, the mechanism underlying the immunosuppression of piglets remains unclear. Activation of the PD-1/PD-L1 axis has been shown to trigger host immunosuppression. Baicalin possesses anti-inflammatory and immunomodulatory functions. However, whether baicalin inhibits PD-1/PD-L1 activation and thus alleviates host immunosuppression has not been investigated. In this study, the effect of baicalin on the attenuation of piglet immunosuppression induced by G. parasuis was evaluated. Seventy piglets were randomly divided into the control group, infection group, levamisole group, BMS-1 group, 25 mg/kg baicalin group, 50 mg/kg baicalin group and 100 mg/kg baicalin group. Following pretreatment with levamisole, BMS-1 or baicalin, the piglets were challenged with 1 × 108 CFU of G. parasuis. Our results showed that baicalin, levamisole and BMS-1 modified routine blood indicators and biochemical parameters; downregulated IL-1ß, IL-10, IL-18, TNF-α and IFN-γ mRNA expression; and upregulated IL-2 and IL-8 mRNA expression in blood. Baicalin, levamisole and BMS-1 increased the proportions of CD3+ T cells, CD3+CD4+ T cells, CD3+CD8+ T cells and CD3-CD21+ B cells in the splenocyte population, increased the proportions of CD3+ T cells, CD3+CD4+ T cells and CD3+CD8+ T cells in the blood, and inhibited PD-1/PD-L1 and TIM-3 activation. Baicalin, levamisole and BMS-1 reduced p-PI3K, p-Akt, and p-mTOR expression, the p-MEK1/2/MEK1/2 and p-ERK1/2/ERK1/2 ratios and increased RAS expression. Baicalin, levamisole and BMS-1 provided substantial protection against G. parasuis challenge and relieved tissue histopathological damage. Our findings might provide new strategies for controlling G. parasuis infection and other immunosuppressive diseases.
Assuntos
Flavonoides , Doenças dos Suínos , Serina-Treonina Quinases TOR , Animais , Flavonoides/farmacologia , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/tratamento farmacológico , Doenças dos Suínos/imunologia , Serina-Treonina Quinases TOR/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Haemophilus parasuis/efeitos dos fármacos , Receptor de Morte Celular Programada 1/metabolismo , Antígeno B7-H1/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Tolerância Imunológica/efeitos dos fármacos , Terapia de Imunossupressão/veterináriaRESUMO
G band, originating from the in-plane vibrations of carbon atoms, is the main signature in Raman spectroscopy of graphene-based systems. It is often used to characterize the sample quality and obtain molecular vibration information. Here we investigate the Raman spectroscopy of ABt-twisted trilayer graphene (ABt-TTG) and observe two enhancement centers for the G band across samples with different twist angles. To understand the origin of these two enhancement centers, we theoretically calculate the G band intensity of ABt-TTG based on the continuum model. We find that the theoretical calculations exhibit two prominent peaks corresponding to the experimental observations after Fermi velocity corrections. We also investigated the real and imaginary parts of Raman resonances, respectively, and explained the origins of two enhancements of ABt-TTG. By using Raman spectroscopy, evolutions of band structures of ABt-TTG with respect to the twist angles can be characterized, which extends the potential applications of the Raman method in the investigation of electronic structures of graphene-based systems.
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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.
Assuntos
Infecções por Haemophilus , Haemophilus parasuis , Doenças dos Suínos , Animais , Antígeno B7-H1 , Infecções por Haemophilus/microbiologia , Infecções por Haemophilus/veterinária , Terapia de Imunossupressão/veterinária , Fosfatidilinositol 3-Quinases , Receptor de Morte Celular Programada 1 , Proteínas Proto-Oncogênicas c-akt , Suínos , Doenças dos Suínos/microbiologia , Serina-Treonina Quinases TORRESUMO
Computed tomography (CT) has become an important technique for analyzing the inner structures of material, biological and energy fields. However, there are often challenges in the practical application of CT due to insufficient data. For example, the maximum rotation angle of the sample stage is limited by sample space or image reconstruction from the limited number of views required to reduce the X-ray dose delivered to the sample. Therefore, it is difficult to acquire CT images with complete data. In this work, an iterative reconstruction algorithm based on the minimization of the image total variation (TV) has been utilized to develop equally sloped tomography (EST), and the reconstruction was carried out from limited-angle, few-view and noisy data. A synchrotron CT experiment on hydroxyapatite was also carried out to demonstrate the ability of the TV-EST algorithm. The results indicated that the new TV-EST algorithm was capable of achieving high-quality reconstructions from projections with insufficient data.
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Poultry necrotic enteritis is an important enteric disease which might be controlled by antibiotics. However, with the excessive use of antibiotics, the phenomenon of drug resistance of Clostridium perfringens is becoming increasingly prominent. Anemoside B4 exhibits important anti-inflammatory, antioxidant and immunomodulatory effects. This study was performed to estimate the effect of Anemoside B4 on chicken necrotic enteritis induced by C. perfringens in vivo and in vitro. In the in vivo experiment we investigated the efficacy of Anemoside B4 on the growth curve, biofilm formation, haemolytic activity, virulence-related gene expression and NF-κB and PI3K/AKT/mTOR activation in Caco-2 cells induced by C. perfringens. The results showed that 12.5-50 µg/mL Anemoside B4 had no antibacterial activity but could inhibit biofilm formation, attenuate haemolytic activity and virulence-related gene expression of C. perfringens and weaken NF-κB and PI3K/Akt/mTOR activation triggered by C. perfringens in Caco-2 cells. In the in vivo experiment, 60 17-day-old healthy White Leghorns were randomly divided into six groups. The growing laying hens of the control group were fed a basic diet, and those of the five challenged groups were fed a basic diet (infection group), added 0.43 g/kg Anemoside B4 (0.43 g/kg Ane group), 0.86 g/kg Anemoside B4 (0.86 g/kg Ane group), 1.72 g/kg Anemoside B4 (1.72 g/kg Ane group) and 40 mg/kg lincomycin (lincomycin group), respectively. All challenged laying hens were infected with 1 × 109 CFU C. perfringens from day 17-20. Blood and intestinal samples were obtained, and the data demonstrated that Anemoside B4 improved the blood biochemical parameters, attenuated jejunum tissue injury, increased the spleen, thymus, bursa of fabricius index, and decreased lesion scores of the jejunum and the ileum. In the jejunum, Anemoside B4 and lincomycin downregulated the expression of IL-1ß, IL-6, IL-10, TNF-α and IFN-γ at mRNA levels. Moreover, Anemoside B4 significantly enhanced both mRNA and protein levels of tight junctions ZO-1, Claudin-1 and MUC-2 in the jejunum. Anemoside B4 weakened p-P65, p-PI3K, p-Akt and p-mTOR protein expression in the jejunum infected by C. perfringens. Diets supplemented with Anemoside B4 alleviated C. perfringens-induced necrotic enteritis in laying hens by inhibiting NF-κB and PI3K/Akt/mTOR signalling pathways and improving intestinal barrier functions.
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Two-dimensional graphene-like dicarbon nitride (C2N) is a newly synthesized metal-free material, which has attracted significant research interest owing to the direct band gap, high carrier mobility, thermal stability, and great tunable properties. However, their application in photocatalytic water splitting has not been well explored. In this work, the properties of photocatalytic water decomposition in heterojunctions composed of C2N and transition metal dichalcogenides (TMDs) with Janus structure MoXY (X, Y = S, Se, Te) are systematically studied by the first-principles calculations based on density functional theory. The results show that except for MoTeS/C2N, the other five heterojunctions have type-â ¡ band alignment, which causes electrons and holes to gather in the C2N and MoXY layer separately. Because the coupled built-in electric field at the intra-layer and inter-layer of asymmetric TMDs with Janus structure forms van der Waals heterojunction, the external electric field is an effective means of modulating the electronic properties of the heterojunction. Under the imposition of an external electric field, the MoSeS/C2N, MoTeSe/C2N, and MoTeS/C2N heterojunctions meet the band edge requirements for the photocatalytic decomposition of water. Detailed analysis demonstrates that the MoSeS/C2N heterojunction could effectively improve the optical absorption properties of monolayer C2N, making it a potential photocatalytic water decomposition material.
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Tuning the thermal properties of materials is considered to be of crucial significance for improving the performance of electronic devices. Along these lines, the development of van der Waals (vdW) heterostructures becomes an effective solution to affect the thermal transport mechanisms. However, vdW interactions usually block phonon transport, which leads to a reduction in thermal conductivity. In this work, we experimentally demonstrate a large enhancement in the thermal conductivity of a vdW heterostructure composed of few-layer hexagonal boron nitride (h-BN) and reduced graphene oxide (RGO). By controlling the reduction temperature of RGO and changing the thickness of h-BN, the thermal conductivity of the RGO is increased by nearly 18 times, namely, from 91 to 1685 W m-1 K-1. Photothermal scanning imaging is used to reveal the changes in the heat transfer and temperature distribution of the h-BN/RGO heterostructure. Both photothermal scanning and Raman spectroscopy experiments show that the vdW interaction between h-BN and RGO can greatly increase the thermal conductivity of RGO, which is in contrast to the conventional understanding that vdW interaction reduces thermal conductivity. Our work paves the way for the manipulation of the thermal conductivity of two-dimensional (2D) heterostructures, which could be of great significance for future nanoelectronic circuits.
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Thermal management plays an important role in miniaturized and integrated nanoelectronic devices, where finding ways to enable efficient heat-dissipation can be critical. 2D materials, especially graphene and hexagonal boron nitride (h-BN), are generally regarded as ideal materials for thermal management due to their high inherent thermal conductivity. In this paper, a new method is reported, which can be used to characterize thermal transport in 2D materials. The separation of pumping from detection can obtain the temperature at different distances from the heat source, which makes it possible to study the heat distribution of 2D materials. Using this method, the thermal conductivity of graphene and molybdenum disulfide is measured, and the thermal diffusion for different shapes of graphene is explored. It is found that thermal transport in graphene changes when the surrounding environment changes. In addition, thermal transport is restricted at the boundary. These processes are accurately simulated using the finite element method, and the simulated results agree well with the experiment. Furthermore, by depositing a layer of h-BN on graphene, the heat-dissipation characteristics of graphene become tunable. This study introduces and describes a new method to investigate and optimize thermal management in 2D materials.
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Grating-based X-ray phase contrast imaging technology is one of the most potential imaging methods in real applications. It can be classified into two categories: interferometry and non-interferometric imaging. The non-interferometric grating-based X-ray phase contrast imaging (NIGPCI) instrument has a great advantage in the forthcoming commercial applications for the flexible system design and the use of large periodic gratings. The performance of the NIGPCI instrument depends on its angular sensitivity to a great extent. Therefore, good angular sensitivity is mandatory in order to obtain high quality phase-contrast images. Several parameters, such as the X-ray spectrum, the inter-grating distances, and the parameters of the three gratings, influence the angular sensitivity of the imaging system. However, the quantitative relationship between the angular sensitivity and grating duty cycle is unclear. Therefore, this paper is devoted to revealing their internal relation by theoretical deduction and emulation of the imaging process with the theories of linear system and Fourier optics. Furthermore, a quantitative analysis method to optimize the duty cycles of gratings is proposed and its applicability to a general NIGPCI system is verified.