SBNeC 2010
Resumo:B.052


Poster (Painel)
B.052Effects of high glucose concentration on oxidative parameters in C6 glioma cells.
Autores:Krista Minéia Wartchow (UFRGS - Univerdidade Federal do Rio Grande do Sul) ; Ana Carolina Tramontina (UFRGS - Univerdidade Federal do Rio Grande do Sul) ; Patrícia Nardin (UFRGS - Univerdidade Federal do Rio Grande do Sul) ; Lucas Tortorelli (UFRGS - Univerdidade Federal do Rio Grande do Sul) ; André Quincozes-santos (UFRGS - Univerdidade Federal do Rio Grande do Sul) ; Carlos Alberto Gonçalves (UFRGS - Univerdidade Federal do Rio Grande do Sul)

Resumo

Introduction: diabetes mellitus is a disease that results in serious complications in central nervous system, including an elevated risk of cognitive dysfunction, dementia and stroke. Hyperglycemia in animal and in vitro models of diabetes is associated with both enhanced production as well as decreased scavenging of ROS, leading to a cellular oxidative stress condition and impaired mitochondrial function. In CNS, astrocytes play critical roles in a number of neural activities, including stress oxidative protection, and their dysfunctions have been proposed in diabetes mellitus. Objectives: the aim of this study was evaluate the effect of hyperglycemia on oxidative status of C6 glioma cells, investigating glutathione content, ROS production, glutamine synthetase activity, nitric oxide production and DNA damage. We also evaluated the effect of high glucose in glutamate uptake, and if S100B stimulates glutamate uptake. Methods: the glioma cells line was obtained from American Type Culture Collection, maintained in DMEM containing 5% calf fetal serum, in 5% CO2 atmosphere and 37oC, with glucose 6 mM (low) or 12 mM (high glucose). Nitric oxide was determined by measurement of nitrite, based on the Griess reaction. Intracellular ROS production was detected using the non-fluorescent cell permeating compound, 2’–7’-dichlorofluorescein diacetate. Glutathione content was measured by a fluorimetric assay with o-phthaldialdeyde. Glutamine synthetase activity was assayed using hydroxylamine as substrate. Glutamate uptake was measured using 0.33 &muCi/ml L-[2,3-3H] glutamate. Results: we found a significant increment of the ROS (about 20%) production in cells treated with high glucose, and nitric oxide production as well (about 60%). Glutathione content and GS decreased about 30% and 20%, respectively in C6 glioma cells cultured in high glucose medium. Also we found an increased DNA damage in about 100% in high glucose treated cells. Glutamate uptake was increased in about 100% in high glucose cultures cells, as well in C6 glioma cells cultured in normal glucose medium, pre-treated with S100B. Conclusions: C6 glioma cells cultured in high-glucose medium, exhibited signals of oxidative and nitrosative stress similar to that find in diabetic patients and other models of diabetic disease (decrease of glutathione, elevated NO, DNA damage). The glutamate uptake was increased, which might be linked altered glutamatergic communication in diabetes mellitus. Together these data emphasize the relevance of astroglia in diabetes mellitus, as well as the importance of glial parameters (e.g. glutamine synthetase) in the evaluation of diabetic disease progression and treatment.


Palavras-chave:  astrocytes, high glucose, oxidativ stress