title: Melatonin inhibits matrix metalloproteinase-9 (MMP-9) activation in the lipopolysaccharide (LPS)-stimulated RAW 264.7 and BV2 cells and a mouse model of meningitis.
abstract: We explored anti-inflammatory potential of melatonin against the lipopolysaccharide (LPS)-induced inflammation in vivo and in vitro. RAW 264.7 and BV2 cells were stimulated by LPS, followed by the treatment with melatonin or vehicle at various time intervals. In a mouse model of meningitis induced by LPS, melatonin (5mg/kg) or vehicle was intravenously injected at 30min postinsult. The activity of matrix metalloproteinase-2 (MMP-2) and metalloproteinase-9 (MMP-9) was determined by gelatin zymography. Nuclear factor-kappa B (NFκB) translocation and binding activity were determined by immunocytochemistry and electrophoretic mobility shift assay (EMSA). Our results showed that either pretreatment or cotreatment with melatonin at 50-500 μm effectively inhibited the LPS-induced proMMP-9 activation in the RAW 264.7 and BV2 cells, respectively (P<0.05). This melatonin-induced proMMP-9 inhibition remained effective when treatment was delayed up to 2 and 6hr postinsult for RAW 264.7 and BV2 cells, respectively (P<0.05 for both groups). Additionally, melatonin significantly attenuated the rises of circulatory and cerebral MMP-9 activity, respectively (P<0.05) and reduced the loss of body weight (P<0.05) in mice with meningitis. Moreover, melatonin (50μm) effectively inhibited nuclear factor-kappa B (NFκB) translocation and binding activity in the LPS-treated RAW 264.7 and BV2 cells, respectively (P<0.05). These results demonstrate direct inhibitory actions of melatonin against postinflammatory NFκB translocation and MMP-9 activation and highlight its ability to inhibit systemic and cerebral MMP-9 activation following brain inflammation.
authors.affiliation: Neurophysiology Laboratory, Neurosurgical Service, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Che-Chao
authors.initials: CC
authors.lastname: Chang
authors.forename: Chih-Hao
authors.initials: CH
authors.lastname: Tien
authors.forename: E-Jian
authors.initials: EJ
authors.lastname: Lee
authors.forename: Wei-Sheng
authors.initials: WS
authors.lastname: Juan
authors.forename: Ying-Hsin
authors.initials: YH
authors.lastname: Chen
authors.forename: Yu-Chang
authors.initials: YC
authors.lastname: Hung
authors.forename: Tsung-Ying
authors.initials: TY
authors.lastname: Chen
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Chen
authors.forename: Tian-Shung
authors.initials: TS
authors.lastname: Wu
mesh_terms: D000818:Animals; D002460:Cell Line; D004195:Disease Models, Animal; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation / Q000187:drug effects; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008581:Meningitis / Q000188:drug therapy* / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9