The protective effect of ceramide in immature rat brain hypoxia-ischemia involves up-regulation of bcl-2 and reduction of TUNEL-positive cells.
Preconditioning brain with tumor necrosis factor alpha (TNF-alpha) can induce tolerance to experimental hypoxia and stroke and ceramide is a downstream messenger in the TNF-alpha signaling pathway. A hypoxic-ischemic (HI) insult in the immature rat injures brain primarily through apoptosis. Apoptosis is regulated by Bcl-2 family proteins. The authors explored whether ceramide protects against HI in the immature rat, and whether Bcl-2 family protein expression is involved. Hypoxia-ischemia was produced in seven-day-old rats by ligating the right carotid artery, followed by 2 hours of 8% oxygen exposure. Thirty minutes after HI, C2-ceramide (150 microg/kg) was injected intraventricularly. Infarct volume was measured 5 days later. C2-ceramide reduced HI-induced brain damage by 45% to 65% compared with HI/dimethyl sulfoxide (DMSO) (vehicle control) or HI only groups. In separate experiments, brains of sham-operated control and HI only animals and animals subjected to HI plus C2-ceramide or DMSO infusion were sampled 6 hours, 24 hours, and 5 days after treatments and analyzed for Bcl-2, Bcl-xl, and Bax expression (Western blotting), and apoptosis (TUNEL assay). Augmented Bcl-2 and Bcl-xl levels in the C2-ceramide treated group were associated with a significant decrease in TUNEL-positive cells. The results support a protective role for ceramide in neonatal HI.
Chen
Y
Y
Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-4128, USA.
Ginis
I
I
Hallenbeck
J M
JM
D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D019254:Genes, bcl-2; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology* / Q000517:prevention & control; D020287:In Situ Nick-End Labeling; D007263:Infusions, Parenteral; D009474:Neurons / Q000187:drug effects / Q000473:pathology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013110:Sphingosine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D013238:Stereotaxic Techniques; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
C064769:N-acetylsphingosine; D018696:Neuroprotective Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; D013110:Sphingosine