title: Matrix metalloproteinases inhibition provides neuroprotection against hypoxia-ischemia in the developing brain.
abstract: The present study was designed to investigate the role of matrix metalloproteinases (MMPs) in the immature brain and the long term effects of early MMPs inhibition after hypoxic-ischemic (HI) injury. HI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8% O(2) for 2 h) in P7 rat pups. GM6001, a broad spectrum MMPs inhibitor, was injected (50 mg/kg or 100 mg/kg) intraperitoneally at 2 h and 24 h after HI injury. Blood-brain barrier (BBB) integrity, brain edema, MMP-2/-9 activity, TIMP-1/-2 and tight junction protein (TJP) level were evaluated using IgG staining, Evan's blue extravasation, brain water content, zymography and western blot. Doxycycline, another MMPs inhibitor, was injected (10 mg/kg or 30 mg/kg) intraperitoneally at 2 h after HI, then BBB integrity and brain edema were measured at 48 h post-HI using brain water content measurement and IgG staining. The long-term effects of early MMPs inhibition (GM6001, 100 mg/kg) were evaluated by neurobehavioral tests, body weight, and brain atrophy measurement. GM6001 attenuated brain edema and BBB disruption at the dosage of 100 mg/kg. MMP-2 activity increased at 24 h and peaked at 48 h after HI, whereas MMP-9 activity peaked at 24 h and tapered by 48 h after HI. MMP-9/-2 activities were significantly attenuated by GM6001 at 24 h and 48 h after HI. The degradation of TJPs (ZO-1 and occludin) at 48 h after HI was reversed by GM6001 treatment. Early MMPs inhibition had long-term effects that attenuated ipsilateral brain tissue loss, and improved neurobehavioral outcomes after HI. These results suggest that early MMPs inhibition with a broad-spectrum inhibitor provides both acute and long-term neuroprotection in the developing brain by reducing TJPs degradation, preserving BBB integrity, and ameliorating brain edema after neonatal HI injury.
authors.affiliation: Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California, USA.
authors.forename: Wanqiu
authors.initials: W
authors.lastname: Chen
authors.forename: Richard
authors.initials: R
authors.lastname: Hartman
authors.forename: Robert
authors.initials: R
authors.lastname: Ayer
authors.forename: Suzanne
authors.initials: S
authors.lastname: Marcantonio
authors.forename: Joel
authors.initials: J
authors.lastname: Kamper
authors.forename: Jiping
authors.initials: J
authors.lastname: Tang
authors.forename: John H
authors.initials: JH
authors.lastname: Zhang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001284:Atrophy / Q000517:prevention & control; D001812:Blood-Brain Barrier / Q000187:drug effects; D001929:Brain Edema / Q000209:etiology / Q000517:prevention & control; D004151:Dipeptides / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D018782:Maze Learning / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors*; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D010750:Phosphoproteins / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
chemical_list: D004151:Dipeptides; D008565:Membrane Proteins; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D018696:Neuroprotective Agents; D010750:Phosphoproteins; D019715:Tissue Inhibitor of Metalloproteinase-1; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D019716:Tissue Inhibitor of Metalloproteinase-2; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9