title: Neurodegeneration in striatum induced by the mitochondrial toxin 3-nitropropionic acid: role of matrix metalloproteinase-9 in early blood-brain barrier disruption?
abstract: Blood-brain barrier (BBB) dysfunction is a potential mechanism involved in progressive striatal damage induced by the mitochondrial excitotoxin, 3-nitropropionic acid (3-NP). After activation by proteases and free radicals, matrix metalloproteinases (MMPs), particularly MMP-9 and -2, can digest the endothelial basal lamina leading to BBB opening. Using CD-1 mice, we show that MMP-9 expression by zymography is increased in the injured striatum compared with the contralateral striatum 2 hr after 3-NP injection [133.50 +/- 57.17 vs 50.25 +/- 13.56; mean +/- SD of optical densities in arbitrary units (A.U.); p < 0.005] and remains elevated until 24 hr (179.33 +/- 78.24 A.U.). After 4 hr, MMP-9 expression and activation are accompanied by an increase in BBB permeability. MMP inhibition attenuates BBB disruption, swelling, and lesion volume compared with vehicle-treated controls. There is a clear spatial relationship between MMP-9 expression and oxidized hydroethidine, indicating reactive oxygen species (ROS) production. Furthermore, transgenic mice that overexpress copper/zinc-superoxide dismutase (SOD1) show decreased lesion size and edema along with decreased immunoreactivity for MMP-9, compared with wild-type littermates (lesion: 38.8 +/- 15.1 and 53.3 +/- 10.3, respectively, p < or = 0.05; edema: 21.8 +/- 11.2 and 35.28 +/- 11, respectively, p < or = 0.05; MMP-9-positive cells: 352 +/- 57 and 510 +/- 45, respectively, p < or = 0.005), whereas knock-out mice deficient in SOD1 display significantly greater swelling (48.65 +/- 17; p < or = 0.05). We conclude that early expression and activation of MMP-9 by ROS may be involved in early BBB disruption and progressive striatal damage after 3-NP treatment.
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects; D001929:Brain Edema / Q000139:chemically induced / Q000517:prevention & control; D003342:Corpus Striatum / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D006151:Guanosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis; D007150:Immunohistochemistry; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects; D019636:Neurodegenerative Diseases / Q000139:chemically induced* / Q000473:pathology / Q000503:physiopathology; D009574:Nitro Compounds; D018384:Oxidative Stress / Q000187:drug effects; D011422:Propionates; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D000072105:Superoxide Dismutase-1
chemical_list: D009574:Nitro Compounds; D011422:Propionates; D006151:Guanosine; C046215:8-hydroxyguanosine; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; C015392:3-nitropropionic acid