Neuroprotective effect of granulocyte colony-stimulating factor after focal cerebral ischemia.
OBJECTIVE
The potential neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF) after glutamate-induced excitotoxicity in cell culture and after focal cerebral ischemia in rats was studied. We hypothesized the existence of the G-CSF receptor (G-CSFR) as a main G-CSF effector on neurons, and immunohistochemistry, immunoblotting, and polymerase chain reaction were performed. The G-CSFR-mediated action was studied by activation of signal transducer(s) and activator(s) of transcription-3 (STAT3) in the periphery of the infarction.


METHODS
Neuroprotection of various G-CSF concentrations on glutamate-induced excitotoxicity was studied in cell culture. In vivo, ischemia was induced by use of a suture occlusion model of the middle cerebral artery (90-minute occlusion) in the rat. Thirty minutes after the induction of ischemia, the animals (n=12 per group) received G-CSF at 60 microg/kg body wt IV for 90 minutes or vehicle (saline). Infarct volume was calculated on the basis of 2,3,5-triphenyltetrazolium chloride staining 24 hours after ischemia. Expression of the G-CSFR was studied by immunohistochemistry and verified by reverse transcription-polymerase chain reaction and immunoblotting. Expression of STAT3 was determined by immunohistochemistry.


RESULTS
In cell culture, G-CSF exhibited a significant neuroprotective effect after glutamate-induced excitotoxicity (P<0.05). A G-CSF concentration of 10 ng/mL was maximally effective, resulting in a nearly complete protection. In vivo, G-CSF reduced infarct volume to 47% (132.0+/-112.7 mm3 versus 278.9+/-91.6 mm3 [P<0.05] in the control group). Immunohistochemistry, Western blotting, and reverse transcription-polymerase chain reaction revealed the existence of G-CSFRs in neurons and glial cells. Animals treated with G-CSF significantly upregulated STAT3 in the periphery of the infarction compared with control animals (P<0.05).


CONCLUSIONS
G-CSF achieved a significant neuroprotective effect in cell culture and after intravenous administration after stroke. Increased STAT3 expression in the penumbra of G-CSF-treated rats suggests mediation by G-CSFR.
Schäbitz
W-R
WR
Department of Neurology, University of Heidelberg, Heidelberg, Germany.
Kollmar
R
R
Schwaninger
M
M
Juettler
E
E
Bardutzky
J
J
Schölzke
M N
MN
Sommer
C
C
Schwab
S
S
D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002544:Cerebral Infarction / Q000473:pathology / Q000517:prevention & control*; D002560:Cerebrovascular Circulation; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D007150:Immunohistochemistry; D002546:Ischemic Attack, Transient / Q000188:drug therapy* / Q000473:pathology; D017078:Laser-Doppler Flowmetry; D008297:Male; D051379:Mice; D009457:Neuroglia / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000096:biosynthesis
D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D018696:Neuroprotective Agents; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C494088:Stat3 protein, rat; D015534:Trans-Activators; D016179:Granulocyte Colony-Stimulating Factor