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VEGF is a homodimeric glycoprotein and cytokine that promotes angiogenesis and neurogenesis while stimulating permeability in endothelial cells. Our hypothesis was that VEGF levels in the brain would be increased by either hypoxia or glucopenia resulting from the energy demands associated with stress or drug treatments; VEGF levels would also be inversely related to tissue and plasma levels of glucose, a source of energy in the brain.
An in-house ELISA test was developed using rrVEGF standard, monoclonal anti-rat VEGF capture antibody (with 50-100% cross-reactivity with rmVEGF120,164 and rhVEGF121,165,189 isoforms), biotinylated anti-rat IgG antibody, streptavidin conjugated with horseradish peroxidase, substrate reagent (composing of stabilized hydrogen peroxide and tetramethylbenzidine), and sulfuric acid stop solution. VEGF concentrations in the samples were proportional to optical density (measured in pg/mL), which was determined on a spectrophotometer set to 450nm.
A significant increase in VEGF levels was observed in LPS treated rats, as this endotoxin induces hypoglycemia as it triggers cytokine cascade. Though the VEGF levels in other experimental groups were generally consistent with the hypothesis they did not attain statistical significance (p<0.05) mostly because of inadequate group sizes.
Our lab researched the effects various drugs and stressors on vascular endothelial growth factor, a protein present in the rat brain that stimulates angiogenesis (formation of blood vessels) and neurogenesis (formation of neurons). Our hypothesis was that treatments inducing hypoglycemia (low glucose levels) and hypoxia (low oxygen levels) would lead to higher observed VEGF levels, as angiogenesis would allow more nutrients to be transported to energy-deficient cells.
We found that in rats treated with lipopolysaccharide (an endotoxin that mimics a virus), VEGF levels significantly rose in accordance with immune response, where the maximum levels were between 6-8 hours after injection. Though all other studies did not reach statistical significance, an overall trend of higher VEGF levels in glucose or oxygen-deprived tissue was seen.
Enzyme Linked Immunoassay (ELISA,) Surgery on an Anesthetized Rat, Microdialysis
Vascular Endothelial Growth Factor, Angiogenesis, Neurogenesis, Stress Response, Hypoglycemia
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