title: Melatonin inhibits postischemic matrix metalloproteinase-9 (MMP-9) activation via dual modulation of plasminogen/plasmin system and endogenous MMP inhibitor in mice subjected to transient focal cerebral ischemia.
abstract: We have shown that melatonin attenuated matrix metalloproteinase-9 (MMP-9) activation and decreased the risk of hemorrhagic transformation following cerebral ischemia-reperfusion. Herein, we investigate the possible involvement of the plasminogen/plasmin system and endogenous MMPs inhibitor underlying the melatonin-mediated MMP-9 inhibition. Mice were subjected to 1-hr ischemia and 48-hr reperfusion of the right middle cerebral artery. Melatonin (5 mg/kg) or vehicle was intravenously injected upon reperfusion. Brain infarction and hemorrhagic transformation were measured. Extracellular matrix damage was determined by Western immunoblot analysis for laminin protein. The activity and expression of MMP-2 and MMP-9 were determined by gelatin zymography, in situ zymography, and Western immunoblot analysis. In addition, the activities of tissue and urokinase plasminogen activators (tPA and uPA) were evaluated by plasminogen-dependent casein zymography. Endogenous plasminogen activator inhibitor (PAI) and tissue inhibitors of MMP (TIMP-1) were investigated using enzyme-linked immunosorbent assay (ELISA) and Western immunoblot analysis, respectively. Cerebral ischemia-reperfusion induced increased MMP-9 activity and expression at 12-48 hr after reperfusion onset. Relative to controls, melatonin-treated animals had significantly decreased MMP-9 activity and expression (P<0.05), in addition to reduced brain infarction and hemorrhagic transformation as well as improved laminin protein preservation. This melatonin-mediated MMP-9 inhibition was accompanied by reduced uPA activity (P<0.05), as well as increased TIMP-1 expression and PAI activity (P<0.05, respectively). These results demonstrate the melatonin's pluripotent mechanisms for attenuating postischemic MMP-9 activation and neurovascular damage, and further support it as an add-on to thrombolytic therapy for ischemic stroke patients.
authors.affiliation: Neurophysiology Laboratory, Neurosurgical Service, Department of Surgery, National Cheng Kung University Medical Center and Medical School, Tainan, Taiwan.
authors.forename: Shih-Huang
authors.initials: SH
authors.lastname: Tai
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Chen
authors.forename: E-Jian
authors.initials: EJ
authors.lastname: Lee
authors.forename: Tsung-Ying
authors.initials: TY
authors.lastname: Chen
authors.forename: Hsiao-Wen
authors.initials: HW
authors.lastname: Lin
authors.forename: Yu-Chang
authors.initials: YC
authors.lastname: Hung
authors.forename: Sheng-Yang
authors.initials: SY
authors.lastname: Huang
authors.forename: Ying-Hsin
authors.initials: YH
authors.lastname: Chen
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Lee
authors.forename: Tian-Shung
authors.initials: TS
authors.lastname: Wu
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005341:Fibrinolysin / Q000378:metabolism*; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D010958:Plasminogen / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D015427:Reperfusion Injury / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism*
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D017395:Plasminogen Activator Inhibitor 1; D019715:Tissue Inhibitor of Metalloproteinase-1; D010958:Plasminogen; D048049:Extracellular Signal-Regulated MAP Kinases; D005341:Fibrinolysin; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D008550:Melatonin