Beta-amyloid toxicity in embryonic rat astrocytes.
The senile plaques of Alzheimer's disease contain a high concentration of beta-amyloid (betaA) protein, which may affect the glial population in the septal nucleus, an area of increased risk in AD. BetaA toxicity was measured in septal glia, via a dose-response experiment, by quantifying the effects of three different doses (0.1, 1, and 10 microM) of betaA on cell survival. Astrocytes from embryonic day-16 rats were grown in serum-free media in a single layer culture. Cells were treated on day in vitro (DIV)1 and survival was determined on DIV3 to ascertain which concentration was most toxic. In a separate set of experiments, an attempt was made to protect glial cells from the degenerative effects of betaA, with treatments of growth factors and estrogen. BetaA (10 microM) treatment was administered on DIV1, on DIV2 the cells were treated with estrogen (EST, 10 nM), insulin-like growth factors (IGF1 and IGF2, each 10 ng/ml), basic fibroblast growth factor (bFGF, 5 ng/ml) or nerve growth factor (NGF, 100 ng/ml), and on DIV3 the cells were visualized and quantified by fluorescence microscopy with DAPI (4,6-diamidino-2-phenylindole). In addition to dose-response and glial protection, experiments were also conducted to determine whether toxic effects were due to apoptosis. Our results suggest that the survival of glial populations is significantly affected in all three concentrations (0.1, 1.0, and 10 microM) of betaA. Glial protection was evident in the presence of NGF, for it showed the significantly highest survival rate relative to the betaA treatment alone. Furthermore, toxic effects of betaA appear to be due primarily to apoptosis. Significant reversal of betaA-induced apoptosis was seen with bFGF and IGF1.
Assis-Nascimento
Poincyane
P
School of Natural and Health Sciences, Barry University, 11300 NE 2nd Ave, Miami Shores, FL 33161, USA.
Jarvis
Karen M
KM
Montague
Jeremy R
JR
Mudd
Laura M
LM
D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects*; D004622:Embryo, Mammalian; D004967:Estrogens / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D007093:Imidazoles; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology; D020932:Nerve Growth Factor / Q000494:pharmacology; D009952:Ornithine / Q000031:analogs & derivatives; D051381:Rats; D017207:Rats, Sprague-Dawley
D016229:Amyloid beta-Peptides; D004967:Estrogens; D007093:Imidazoles; D016222:Fibroblast Growth Factor 2; C107968:N(delta)-(5-methyl-4-oxo-2-imidazolin-2-yl)ornithine; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D020932:Nerve Growth Factor; D009952:Ornithine