Mechanism of Buyang Huanwutang in Regulating Macrophage Cell Polarization Based on TLR4/NF-κB/NLRP3 Pathway / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of Buyang Huanwutang in regulating macrophage polarization based on the Toll-like receptor 4 （TLR4） / nuclear factor-κB （NF-κB） / nucleotide-binding oligomerization domain-like receptor 3 （NLRP3） pathway. MethodRAW264.7 macrophages were intervened with lipopolysaccharide （LPS） of different concentrations （0， 1.25， 2.5， 5， 10， 20， 40， and 80 mg·L-1） for 24 hours. Cell Counting Kit-8 （CCK-8） assay was used to determine the cell viability of RAW264.7 macrophages. The optimal concentration was chosen to establish an in vitro inflammation model induced by LPS. Cells were divided into a blank group （20% blank serum）， a model group （20% blank serum + 10 mg·L-1 LPS）， a model control group （20% FBS + 10 mg·L-1 LPS）， low-， medium-， and high-dose （5%， 10%， and 20%） Buyang Huanwutang-containing serum groups， a high-dose （20%） Buyang Huanwutang combined with NLRP3 inhibitor MCC950 （50 μmol·L-1） group， a high-dose （20%） Buyang Huanwutang combined with reactive oxygen species （ROS） inhibitor NAC （10 μmol·L-1） group， and a high-dose （20%） Buyang Huanwutang combined with NF-κB inhibitor PDTC （10 μmol·L-1） group. Enzyme-linked immunosorbent assay （ELISA） was used to detect the expression of interleukin-1β （IL-1β）， interleukin-18 （IL-18）， and tumor necrosis factor-α （TNF-α） in RAW264.7 macrophages. Flow cytometry was employed to measure ROS levels in macrophages. Western blot was used to determine the protein expression of M1-type macrophage-related factors inducible nitric oxide synthase （iNOS） and TNF-α， M2-type macrophage-related factors arginase-1 （Arg-1） and interleukin-10 （IL-10）， as well as the proteins in the TLR4/NF-κB/NLRP3 pathway. ResultCCK-8 results indicated that under 10 mg·L-1 LPS stimulation， RAW264.7 macrophages exhibited the highest cell viability （P<0.01）. Compared with the blank group， the model group showed significantly increased levels of IL-1β， IL-18， and TNF-α （P<0.05，P<0.01）， increased ROS expression （P<0.05，P<0.01）， increased protein expression of M1-type macrophage factors iNOS and TNF-α （P<0.01）， decreased protein expression of M2-type macrophage factors Arg-1 and IL-10 （P<0.05，P<0.01）， and upregulated expression levels of TLR4， myeloid differentiation factor 88 （MyD88）， phosphorylated inhibitor of NF-κB （p-IκB）/NF-κB inhibitor （IκB）， phosphorylated NF-κB （p-NF-κB） p65/NF-κB p65， NLRP3， apoptosis-associated speck-like protein containing a CARD （ASC）， and pro-Caspase-1 （P<0.05， P<0.01）. Compared with the model group， all Buyang Huanwutang-treated groups and inhibitor groups significantly reduced levels of IL-1β， IL-18， and TNF-α （P<0.01）， suppressed the expression of inflammatory factors in RAW264.7 macrophages， decreased cellular ROS expression levels （P<0.01）， downregulated M1-type macrophages iNOS and TNF-α protein expression （P<0.01）， upregulated M2-type macrophages Arg-1 and IL-10 protein expression （P<0.01）， and lowered protein expression levels of TLR4， MyD88， p-IκB/IκB， p-NF-κB p65/NF-κB p65， NLRP3， ASC， and pro-Caspase-1 （P<0.05， P<0.01）. ConclusionBuyang Huanwutang can improve macrophage inflammation， potentially by reducing macrophage ROS levels， inhibiting RAW264.7 macrophage polarization， and downregulating the protein expression levels of the TLR4/NF-κB/NLRP3 pathway.

Establishment of a mouse model of pneumonia with an isolated epidemic ST23 Klebsiella pneumonia strain / 中华微生物学和免疫学杂志

Objective To establish a mouse model of pneumonia with C57BL/6 and MyD88KO mice after infection with an isolated ST23 Klebsiella pneumonia (KP) strain, which was an epidemic strain and identified by multilocus sequence typing (MLST). Methods Fifty C57BL/6 mice were randomly di-vided into three groups:KP infection,control and immunosuppressive groups. Thirty MyD88KO mice were divided into KP infection and control groups. All mice in the KP infection groups were infected with 50 μl of ST23 KP strain through nasal dripping. Equal volume of PBS was used to set up the control groups. Mice in the immunosuppressive group were first injected with cyclophosphamide for three days and then infected with equal volume of ST23 KP strains through nasal dripping. Clinical signs and survival curves during KP infec-tion were monitored. Moreover,pulmonary bacterial loads and histopathological changes in the KP-infected mice were detected at different time points. Results ST23 KP-infected C57BL/6 mice showed inflammatory cell infiltration in lung tissues on the 10th day and remained alive on the 21st day. All ST23 KP-infected MyD88KO mice died on the 5th day with severe histopathological damage in lung tissues. C57BL/6 mice that pretreated with cyclophosphamide had similar symptoms with MyD88KO mice after infection and died on the 5th day. Some critical inflammatory mediators such as TNF-a,nitric oxide synthase 1 (NOS1) and NF-κBp65 were up-regulated in lung tissues of mice after KP infection. No inflammatory syndromes were found in the mice of PBS control groups. Conclusion This study suggests that the mouse model of pneumonia is successfully established with KP strain. It will help researchers to study the characteristics and pathogenesis of ST23 KP strain-induced pneumonia and to seek safe treatments in the future.