title: Involvement of matrix metalloproteinases-2 and -9 in the formation of a lacuna-like cerebral cavity.
abstract: We used a modified pial vessel disruption (PVD) protocol with adult male Wistar rats to mimic small-vessel stroke in the cerebral cortex. Within 3 weeks, this lesion develops into a single lacuna-like cavity, which is fluid-filled and encapsulated by reactive astrocytes. Minocycline treatment that commences 1 hr after lesion and continues for 6 days prevents the cavitation and causes a filling of the lesion with reactive astrocytes and no barrier. Here, we determined whether inhibition of matrix metalloproteinases-2 and -9 (MMPs) mediates this minocycline action. Confocal microscopy revealed increased punctate staining of MMPs inside the lesion sites after 2 days of PVD. Astrocytes lined the lesion border but showed sparse localization inside the lesion. In contrast, increased MMP levels inside the lesion coincided with increased ED1 or OX-42 immunostaining, suggesting that MMP elevation reflected increased secretions from microglia/macrophages. Imaging analyses also revealed that minocycline administered for 2 days before animal euthanasia, significantly decreased MMP levels within the lesion. Moreover, Western blot analysis of cortical tissue extracts showed a significant 30-40% upregulation of MMPs 2 days after lesion. Minocycline administered 2 hr before the lesion significantly inhibited both MMP-9 and MMP-2 levels by ∼40%. In contrast, minocycline administered 1 hr after the lesion only decreased MMP-9 levels by ∼30%. Because MMP inhibition with batimastat injection also prevented cavity formation at 21 days, we conclude that minocycline prevented the creation of a lacuna-like cyst in the cerebral cortex by inhibiting the MMP secretion from microglia in the affected tissue.
authors.affiliation: Department of Physiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. frank.cayabyab@usask.ca
authors.forename: Francisco S
authors.initials: FS
authors.lastname: Cayabyab
authors.forename: Krishnamoorty
authors.initials: K
authors.lastname: Gowribai
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Walz
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D004195:Disease Models, Animal; D053331:Ectodysplasins / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D017628:Microglia / Q000473:pathology; D008911:Minocycline / Q000494:pharmacology / Q000627:therapeutic use; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D011480:Protease Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D020521:Stroke / Q000150:complications / Q000188:drug therapy; D059409:Stroke, Lacunar / Q000201:enzymology* / Q000209:etiology / Q000517:prevention & control; D013876:Thiophenes / Q000494:pharmacology / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D039481:CD11b Antigen; D053331:Ectodysplasins; D005904:Glial Fibrillary Acidic Protein; D011480:Protease Inhibitors; D013876:Thiophenes; D010649:Phenylalanine; C080985:batimastat; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D008911:Minocycline