Recombinant osteopontin attenuates brain injury after intracerebral hemorrhage in mice.
BACKGROUND
Osteopontin (OPN), an extracellular matrix glycoprotein, has been reported to inhibit inducible nitric oxide synthase (iNOS). We examined if recombinant OPN (r-OPN) inhibits iNOS and prevents brain injury in a mouse collagenase-induced intracerebral hemorrhage (ICH) model.


METHODS
One hundred one mice were randomly assigned to five groups: sham, ICH + vehicle, ICH + r-OPN (10, 50, or 100 ng per mouse) groups. Vehicle or r-OPN was administered via an intracerebroventricular infusion 20 min pre-ICH. Neurological scores and brain water content were evaluated at 24 and 72 h, and hemoglobin assay, Nissl staining and Western blot for iNOS, Stat1, matrix metalloproteinase (MMP)-9 and zonula occludens (ZO)-1 were performed at 24 h post-ICH.


RESULTS
r-OPN did not affect hematoma formation. Middle (50 ng)- and high (100 ng)-dose, but not low (10 ng)-dose of r-OPN treatment significantly improved neurological scores and brain water content compared with the vehicle group. The protective effect of r-OPN was associated with significantly rescued neuronal cells in the peri-hematoma region as well as a decrease in the Stat1 phosphorylation, iNOS induction, MMP-9 activation, and ZO-1 degradation.


CONCLUSIONS
This study suggests that r-OPN may down-regulate iNOS expression by the inhibition of Stat1 phosphorylation, and therefore suppressing the MMP-9 activation, preventing ICH-induced brain injury in mice.
Wu
Bihua
B
Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA 92350, USA.
Ma
Qingyi
Q
Suzuki
Hidenori
H
Chen
Chunhua
C
Liu
Wenwu
W
Tang
Jiping
J
Zhang
John
J
D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D001929:Brain Edema / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D017364:Collagenases / Q000633:toxicity; D004195:Disease Models, Animal; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018632:Mice, Inbred SENCAR; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000378:metabolism; D053495:Osteopontin / Q000494:pharmacology*; D010750:Phosphoproteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology*; D050794:STAT1 Transcription Factor / Q000378:metabolism; D014867:Water / Q000378:metabolism; D062826:Zonula Occludens-1 Protein
D008565:Membrane Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D014867:Water; D053495:Osteopontin; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D017364:Collagenases; D020780:Matrix Metalloproteinase 9