title: Very brief focal ischemia simulating transient ischemic attacks (TIAs) can injure brain and induce Hsp70 protein.
abstract: This study examined very brief focal ischemia that simulates transient ischemic attacks (TIAs) that occur in humans. Adult rats were subjected to sham operations or 5 min, 10 min, or 2 h of middle cerebral artery (MCA) ischemia using the suture (thread) model. Hsp70 protein was induced 24 h, 48 h and 72 h later in neurons throughout the entire MCA territory in many but not all animals. Following 5- and 10-minute MCA occlusions, 9 of 32 animals (28%) had microinfarcts mostly in dorsal lateral striatum. Uncommon Hsp70 stained intracellular cytoplasmic inclusions, some of which co-localized with activated caspase-3, were detected in microglia, macrophages, astrocytes and oligodendrocytes. Hsp70 stained neurons were TUNEL negative at 24 h and 48 h whereas some Hsp70 stained neurons were TUNEL positive at 72 h after reperfusion. Hsp70 positive, activated "bushy" microglia and Hsp70 negative, activated "polarized" or rod-shaped microglia were located outside of the microinfarcts. Thus, experimental focal ischemia simulating TIAs can: induce Hsp70 protein throughout the ischemic vessel territory; produce Hsp70 protein positive glial inclusions; activate Hsp70 positive and negative microglia; and cause microinfarcts in some animals.
authors: Department of Neurology and M.I.N.D. Institute, University of California at Davis, Sacramento, CA 95817, USA. xzhan@ucdavis.edu
authors: Xinhua
authors: X
authors: Zhan
authors: Charles
authors: C
authors: Kim
authors: Frank R
authors: FR
authors: Sharp
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology*; D053148:Caspase 3 / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D002479:Inclusion Bodies / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D020768:Middle Cerebral Artery / Q000473:pathology; D009457:Neuroglia / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005904:Glial Fibrillary Acidic Protein; D018840:HSP70 Heat-Shock Proteins; D053148:Caspase 3