Endogenous plasminogen activator expression after embolic focal cerebral ischemia in mice

Citation
My. Ahn et al., Endogenous plasminogen activator expression after embolic focal cerebral ischemia in mice, BRAIN RES, 837(1-2), 1999, pp. 169-176
Citations number
51
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
BRAIN RESEARCH
ISSN journal
0006-8993 → ACNP
Volume
837
Issue
1-2
Year of publication
1999
Pages
169 - 176
Database
ISI
SICI code
0006-8993(19990807)837:1-2<169:EPAEAE>2.0.ZU;2-X
Abstract
Urokinase-type plasminogen activator (u-PA) and tissue-type plasminogen act ivator (t-PA) play important roles in fibrinolysis, cell migration, tissue destruction, angiogenesis and tissue remodeling. u-PA and t-PA activity in tissue are tightly regulated by plasminogen activator inhibitor-1 (PAI-1). However, little is known of the activity of endogenous plasminogen activato rs (PAs) and PAI-1 in ischemic brain. To evaluate whether cerebral ischemic injury induces endogenous PAs and PAI-1, we measured PA activity from brai n homogenates, and examined the expression of t-PA mRNA, u-PA mRNA and PAI- 1 mRNA from brain homogenates in C57BL/6J mice (n = 45) weighing 29-35 g in which the middle cerebral artery (MCA) was occluded by a fibrin-rich clot. Brain homogenates were prepared for direct casein zymography from control non-ischemic mice (n = 4) and mice at 2 h (n = 5), 4 h (n = 5), and 24 h (n = 4) after MCA occlusion (MCAO). Also, u-PA and t-PA knockout mice at 4 h (n = 2, each) after MCAO were used as a negative control for direct casein zymography. Frozen sections for in situ zymography were obtained from contr ol mice (n = 2) and mice at 2 h, 4 h, and 24 h (n = 2, per time point) afte r clot occlusion. Brain homogenates were prepared for reverse transcriptase -polymerase chain reaction (RT-PCR) to examine t-PA mRNA, u-PA mRNA and PAI -1 mRNA expression from control non-ischemic mice (n = 4) and mice at 2 h ( n = 5), 4 h (n = 5), and 24 h (n = 5) after MCAO. By direct casein zymograp hy, u-PA activity increased at 4 h (P < 0.05), and 24 h (P < 0.05) after st roke in the ischemic hemisphere compared with the non-ischemic mice. Activi ty of t-PA in ischemic brain was not significantly different from the contr ol group. As measured by in situ zymography, PA activity, most likely u-PA, was present in the ischemic hemisphere. By RT-PCR, expression of PAI-1 mRN A, but not u-PA mRNA and t-PA mRNA, increased 3-, 15- and 25-folds in the i schemic hemisphere at 2 h, 4 h and 24 h after stroke, respectively, compare d with control mice. This study demonstrates that PAI-1 mRNA and u-PA activ ity increase in mouse brain after stroke. (C) 1999 Elsevier Science B.V. Al l rights reserved.