Effects Of Glutamate And Pyruvate On Astrocyte Tolerance To Oxidative Stress

Accumulating studies have confirmed that oxidative stress is related to a variety of neurodegenerative diseases.Under normal physiological conditions,the level of ATP in astrocytes maintains a dynamic balance,but oxidative stress can significantly inhibit the synthesis of ATP,trigger a series of cellular processes,and eventually lead to cell death.In this study,we found that H₂O₂can reduce the level of glutamate in astrocytes,and exogenous glutamate can significantly enhance the survival of astrocytes under oxidative stress.Pyruvate has an important protective effect in the recovery period after oxidative stress.Because the glycolysis step of glucose metabolism is more vulnerable to oxidative stress than TCA cycle.In the absence of exogenous pyruvate or endogenous production from glycolysis,glutamate can be an prefer metabolite for TCA and is key to sustain a vital level of ATP synthesis,which is key to better recovery from oxidative stress.Objective To explore the effect of glutamate metabolism on astrocyte activity and ATP synthesis under oxidative stressmethod Oxidative stress was induced by exogenous H₂O₂.Glutamic acid and pyruvic acid were used to intervene.CCK-8 and fluorescence staining were used to detect cell viability.Intracellular ATP concentration and HPLC were used to measure the effect of glutamic acid on oxidative stress.Objective to study the effects of glutamate and pyruvate on ATP synthesis and cell activity of astrocytes in the process of oxidative stimulation and the recovery process after elimination of stimulation.The image data were analyzed by Leica Las X and image J.Results(1)After astrocytes were treated with 0-2000?M H₂O₂for 15 min and 30 min,the cell activity decreased significantly.Pretreatment with 200?M glutamate could significantly improve the cell activity.(2)After H₂O₂treatment,exogenous administration of pyruvate could significantly increase cell survival,but exogenous administration of glutamate had no significant effect.(3)H₂O₂treatment decreased intracellular ATP level in a time and dose-dependent manner,and glutamate pretreatment significantly alleviated this decrease.(4)H₂O₂treatment accelerated the intracellular glutamate consumption,glutamate pretreatment could enhance the intracellular glutamate reserve,making intracellular glutamate more tolerant to the consumption caused by H₂O₂treatment.(5)Acute administration of high concentration glutamate also partially alleviated the decrease of intracellular ATP induced by H₂O₂treatment..Conclusion(1)Glutamate pretreatment can reduce the damage of astrocytes stimulated by H₂O₂.Glutamate provides the metabolic substrate for the tricarboxylic acid cycle after glycolysis inactivation.(2)In the case of glutamate pretreatment,exogenous pyruvate bypassed the inhibition of glycolysis and directly entered the tricarboxylic acid cycle to synthesize ATP during the recovery period after H2O2stimulation,which was beneficial to maintain the cell activity.(3)In short-term stimulation with H₂O₂,high concentration of glutamate(1?100 m M)could also protect the ATP level in astrocytes,but the effect was not as good as low concentration of glutamate pretreatment.