Fructose-1,6-bisphosphate does not preserve ATP in hypoxic-ischemic neonatal cerebrocortical slices.
Fructose-1,6-bisphosphate (FBP), an endogenous intracellular metabolite in glycolysis, was found in many preclinical studies to be neuroprotective during hypoxia-ischemia (HI) when administered exogenously. We looked for HI neuroprotection from FBP in a neonatal rat brain slice model, using 14.1 T (1)H/(31)P/(13)C NMR spectroscopy of perchloric acid slice extracts to ask: 1) if FBP preserves high energy phosphates during HI; and 2) if exogenous [1-(13)C]FBP enters cells and is glycolytically metabolized to [3-(13)C]lactate. We also asked: 3) if substantial superoxide production occurs during and after HI, thinking such might be treatable by exogenous FBP's antioxidant effects. Superfused P7 rat cerebrocortical slices (350 mum) were treated with 2 mM FBP before and during 30 min of HI, and then given 4 h of recovery with an FBP-free oxygenated superfusate. Slices were removed before HI, at the end of HI, and at 1 and 4 h after HI. FBP did not improve high energy phosphate levels or change (1)H metabolite profiles. Large increases in [3-(13)C]lactate were seen with (13)C NMR, but the lactate fractional enrichment was always (1.1+/-0.5)%, implying that all of lactate's (13)C was natural abundance (13)C, that none was from metabolism of (13)C-FBP. FBP had no effect on the fluorescence of ethidium produced from superoxide oxidation of hydroethidine. Compared to control slices, ethidium fluorescence was 25% higher during HI and 50% higher at the end of recovery. Exogenous FBP did not provide protection or enter glycolysis. Its use as an antioxidant might be worth studying at higher FBP concentrations.
Liu
Jia
J
Department of Anesthesia and Perioperative Medicine, The University of California San Francisco, San Francisco, CA 94143, USA.
Hirai
Kiyoshi
K
Litt
Lawrence
L
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D005635:Fructosediphosphates / Q000378:metabolism / Q000494:pharmacology*; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000517:prevention & control*; D018696:Neuroprotective Agents / Q000378:metabolism / Q000494:pharmacology*; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013057:Spectrum Analysis; D013481:Superoxides / Q000378:metabolism
D005635:Fructosediphosphates; D018696:Neuroprotective Agents; D013481:Superoxides; D000255:Adenosine Triphosphate; C029063:fructose-1,6-diphosphate