Temporal expression of osteopontin and CD44 in rat brains with experimental cryolesions.
Expression of osteopontin and CD44 in the brain was studied after cryolesioning to understand how osteopontin and its receptor, CD44, are involved in processes in the brains of rats with cryolesions. Western blot analysis showed that osteopontin increased significantly at days 4 and 7 post-injury and declined slightly thereafter in cryolesioned brains in comparison with levels in sham-operated controls. An immunohistochemical study localized osteopontin in activated microglia/macrophages in the core lesions, where the majority of macrophages proliferate. Osteopontin was also detected temporarily in some neurons and a few astrocytes in the lesion periphery on days 4 and 7 post-injury, but the immunoreactivity in macrophages, neurons, and astrocytes disappeared by day 14 post-injury. There was some CD44, a receptor for osteopontin, in the brain cells of sham-operated rats. After injury, intense CD44 immunostaining was seen in the majority of macrophages and in reactive astrocytes, but not in neurons, in the ipsilateral lesions after day 4 post-injury, and this immunoreactivity remained on day 14 post-injury. These findings suggest that activated microglia/macrophages and some neurons are major sources of osteopontin during the early stage of brain damage induced by a cryolesion and that osteopontin interacts with CD44 expressed on astrocytes and activated microglia/macrophages in the damaged cerebral cortex, possibly mediating cell migration after cryolesioning in the rat brain.
Shin
Taekyun
T
Department of Veterinary Medicine, Cheju National University, Jeju 690-756, South Korea. shint@cheju.ac.kr
Ahn
Meejung
M
Kim
Heechul
H
Moon
Changjong
C
Kang
Tae-Young
TY
Lee
Joo-Myoung
JM
Sim
Ki-Bum
KB
Hyun
Jin-Won
JW
D000818:Animals; D001253:Astrocytes / Q000276:immunology / Q000378:metabolism; D016923:Cell Death / Q000502:physiology; D004195:Disease Models, Animal; D005615:Freezing; D005625:Frontal Lobe / Q000276:immunology / Q000293:injuries* / Q000378:metabolism* / Q000473:pathology; D018960:Hyaluronan Receptors / Q000378:metabolism*; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D008297:Male; D053495:Osteopontin; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000378:metabolism*
D018960:Hyaluronan Receptors; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin