The effect of Panax notoginseng saponins on oxidative stress induced by PCV2 infection in immune cells:in vitro and in vivo studies

Background@#Panax notoginseng saponins (PNS) are bioactive substances extracted from P. notoginseng that are widely used to treat cardiovascular and cerebrovascular diseases and interstitial diseases. PNS have the functions of scavenging free radicals, anti-inflammation, improving blood supply for tissue and so on. @*Objectives@#The aim of this study was to investigate the effects of PNS on the oxidative stress of immune cells induced by porcine circovirus 2 (PCV2) infection in vitro and in vivo. @*Methods@#Using an oxidative stress model of PCV2 infection in a porcine lung cell line (3D4/2 cells) and mice, the levels of nitric oxide (NO), reactive oxygen species (ROS), total glutathione (T-GSH), reduced glutathione (GSH), and oxidized glutathione (GSSG) and the activities of xanthine oxidase (XOD), myeloperoxidase (MPO) and inducible nitric oxide synthetase (iNOS) were determined to evaluate the regulatory effects of PNS on oxidative stress. @*Results@#PNS treatment significantly reduced the levels of NO and ROS, the content of GSSG and the activities of XOD, MPO, and iNOS (p < 0.05), while significantly increasing GSH and the ratio of GSH/GSSG in infected 3D4/2 cells (p < 0.05).Similarly, in the in vivo study, PNS treatment significantly decreased the level of ROS in spleen lymphocytes of infected mice (p < 0.05), increased the levels of GSH and T-GSH (p < 0.05), significantly decreased the GSSG level (p < 0.05), and decreased the activities of XOD, MPO, and iNOS. @*Conclusions@#PNS could regulate the oxidative stress of immune cells induced by PCV2 infection in vitro and in vivo.

Inhibitory effect of polysaccharide of Sargassum weizhouense on PCV2 induced inflammation in mice by suppressing histone acetylation.

Seaweeds are excellent source of bioactive compounds and seaweed-derived polysaccharides have demonstrated an array of biological effects. Here, we investigated the effect of polysaccharide of Sargassum weizhouense (PSW) on the inflammatory response in porcine circovirus type 2 (PCV2) infected mice and the underlying mechanism was studied according to the histone acetylation. After PCV2 infection, the levels of TNF-α, IL-1ß, IL-6, IL-8, IL-10, MCP-1, COX-1, COX-2 and HAT in both serum and spleen were significantly increased (P <0.05). The mRNA expression of TNF-α, IL-6, IL-10 and NF-κB p65 were elevated in PCV2 infected mice (P <0.05). The HDAC content in both serum and spleen as well the mRNA expression of HDAC1 were greatly decreased (P <0.05). PSW treatment dramatically inhibited the secretions of inflammatory cytokines and HATs, reduced mRNA expression of TNF-α, IL-6, IL-10 and NF-κB p65, but promoted HDAC secretion and mRNA expression of HDAC1 in PCV2-infected mice. The acetylation of both H3 and H4 was significantly up-regulated in PCV2-infected mice, and strongly inhibited by PSW treatment (P <0.01). These results suggested that PCV2 mediate the equilibrium between HATs and HDACs, alternate the histone acetylation and thus DNA packaging, and then activate the transcription of inflammatory cytokines. PSW could inhibit the histone acetylation and the production of inflammatory cytokines, showing excellent potentials in improving the resistance of host against PCV2 infection.

Enhanced Cell Surviving against Oxidative Stress and Treg-inducing Ability of Dedifferentiated Human Umbilical Cord Mesenchymal Stem Cells Modified by IDO Gene / 中山大学学报(医学科学版)

@#【Objective】 To investigate whether the dedifferented human umbilical cord mesenchymal stem cells（hMSC）modified by IDO gene can get improved ability to survive oxidative stress as well as to induce regulatory T（Treg） lymphocytes.【Methods】The dedifferentiated hMSC（De- hMSC）were obtained by a transient adipogenic induction and subsequent recovery culture in normal medium. The IDO gene modified De-hMSC （IDO/De-hMSC）were prepared by retroviral infection using recombinant retrovirus harboring IDO gene. The De- hMSC infected by retrovirus containing ZsGreen1 gene，the non- infected De- hMSC and hMSC were set as controls. Exogenous expression of IDO protein was confirmed by Western blot. Flow cytometry analysis was performed to detect the immunophenotype of IDO/De- hMSC ， and their osteogenic/adipogenic differentiation abilities were also assessed. Cell survival rates under the oxidative stress of 300 μmol/L t- BHP were determined by Annexin V- FITC/PI double staining flow cytometry. Human peripheral blood mononuclear cells （PBMC） were isolated and treated with conditioned medium containing the culture supernatant of hMSC，De-hMSC，Mock/De-hMSC and IDO/De-hMSC，respectively. Changes in the proportion of CD4+ CD25+ CD127low Treg cells in PBMC were determined by triple fluorescent labeling flow cytometry.【Results】The De-hMSC modified by IDO gene still have the immunophenotype as well as the osteogenic/adipogenic differentiation abilities that are typical of mesenchymal stem cells. When challenged by 300 μmol/L t-BHP，the number of viable cells in De-hMSC significantly elevated compared with hMSC（P<0.05），and the survival advantage of De-hMSC was not obviously affected by IDO gene modification（P>0.05）. Conditioned medium containing the supernatant from IDO/De- hMSC dramatically up- regulated the percentage of CD4+CD25+CD127low Treg cells in PBMC in contrast to the control groups（P<0.05）.【Conclusions】IDO/ De- hMSC have the same immunophenotype and differentiation capacity as the native hMSC ，and can simultaneously enhance the ability of hMSC to survive against oxidative stress and to induce Treg cells ，which may be a potential modification strategy of mesenchymal stem cells for immunosuppressive therapy.