title: Rhubarb Antagonizes Matrix Metalloproteinase-9-induced Vascular Endothelial Permeability.
abstract: BACKGROUND
  Intact endothelial structure and function are critical for maintaining microcirculatory homeostasis. Dysfunction of the latter is an underlying cause of various organ pathologies. In a previous study, we showed that rhubarb, a traditional Chinese medicine, protected intestinal mucosal microvascular endothelial cells in rats with metastasizing septicemia. In this study, we investigated the effects and mechanisms of rhubarb on matrix metalloproteinase-9 (MMP9)-induced vascular endothelial (VE) permeability.
  
  
  METHODS
  Rhubarb monomers were extracted and purified by a series of chromatography approaches. The identity of these monomers was analyzed by hydrogen-1 nuclear magnetic resonance (NMR), carbon-13 NMR, and distortionless enhancement by polarization transfer magnetic resonance spectroscopy. We established a human umbilical vein endothelial cell (HUVEC) monolayer on a Transwell insert. We measured the HUVEC permeability, proliferation, and the secretion of VE-cadherin into culture medium using fluorescein isothiocyanate-dextran assay, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, and enzyme-linked immunosorbent assay, respectively, in response to treatment with MMP9 and/or rhubarb monomers.
  
  
  RESULTS
  A total of 21 rhubarb monomers were extracted and identified. MMP9 significantly increased the permeability of the HUVEC monolayer, which was significantly reduced by five individual rhubarb monomer (emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl)-β-D-glucose, daucosterol linoleate, and rhein) or a combination of all five monomers (1 μmol/L for each monomer). Mechanistically, the five-monomer mixture at 1 μmol/L promoted HUVEC proliferation. In addition, MMP9 stimulated the secretion of VE-cadherin into the culture medium, which was significantly inhibited by the five-monomer mixture.
  
  
  CONCLUSIONS
  The rhubarb mixture of emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl)-β-D-glucose, daucosterol linoleate, and rhein, at a low concentration, antagonized the MMP9-induced HUVEC monolayer permeability by promoting HUVEC proliferation and reducing extracellular VE-cadherin concentrations.
authors.affiliation: Department of Critical Care Medicine, Jinan Military General Hospital, Jinan, Shandong 250031, China.
authors.forename: Yun-Liang
authors.initials: YL
authors.lastname: Cui
authors.affiliation: Department of Emergency Medicine, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Critical Care Medicine, Jinan Military General Hospital, Jinan, Shandong 250031, China.
authors.forename: Zhao-Tao
authors.initials: ZT
authors.lastname: Tian
authors.affiliation: Department of Emergency Medicine, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
authors.forename: Zhao-Fen
authors.initials: ZF
authors.lastname: Lin
authors.affiliation: Department of Emergency Medicine, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China.
authors.forename: De-Chang
authors.initials: DC
authors.lastname: Chen
mesh_terms: D015820:Cadherins / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D012250:Rheum / Q000737:chemistry*
chemical_list: D015820:Cadherins; D004365:Drugs, Chinese Herbal; D020780:Matrix Metalloproteinase 9