Relationship between S100beta and GFAP expression in astrocytes during infarction and glial scar formation after mild transient ischemia.
The expression of astrocyte marker proteins (S100beta and GFAP) during infarction and glial scar formation after transient middle cerebral artery (MCA) occlusion was examined using double immunostaining. S100beta immunoreactivity markedly decreased in the core of the injured area when observed immediately after reperfusion and did not increase again. In the periphery, however, S100beta expression increased, showing that S100beta synthesis was up-regulated. S100beta+/iNOS+ astrocytes in the periphery were observed from day 1, when small infarct areas were detectable, up to day 5, when infarct expansion had almost ended. TUNEL+ cells in the periphery were present from days 1 to 5. S100beta+/TUNEL+ cells were observed centrally and around the periphery of the injured area, predicting that cell death contributes to the increase of S100beta concentration in the injured area. Our results suggest that (1) higher concentration of S100beta in the extracellular space due to S100beta leakage from damaged astrocytes leads to up-regulation of S100beta synthesis and induction of inducible nitric oxide synthase (iNOS) synthesis in astrocytes, contributing to infarct expansion that results in DNA damage or cell death via NO and ROS production, and (2) GFAP, but not S100beta, is a main contributor to glial scar formation. On day 1 postreperfusion, the microdiascopic images of the injured areas from the unstained thick sections or the areas detected by S100beta immunoreactivity were larger than those of the infarct areas detected by hematoxylin--eosin (HE)-staining. The difference between these sizes might be useful to predict infarct expansion.
Cell Biology Section, Division of Basic Research, Louis Pasteur Center for Medical Research, 103-5 Sakyo, Tanaka, Monzen-cho, Kyoto 606-8225, Japan. yyasuda@lpc-dns.louis-pasteur.or.jp
Yuko
Y
Yasuda
Narito
N
Tateishi
Taiji
T
Shimoda
Souichi
S
Satoh
Eriko
E
Ogitani
Setsuya
S
Fujita
D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers; D002544:Cerebral Infarction / Q000378:metabolism / Q000473:pathology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D005911:Gliosis / Q000378:metabolism* / Q000473:pathology; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D009414:Nerve Growth Factors; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*; D012720:Severity of Illness Index
D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat