Protective Effects Of Sodium Para-Aminosalicylate On Concentrations Of Amino Acid Neurotransmitters Of Manganese-Exposed Thalamus Astrocyte In Vitro

Objective The purpose of this article is to explore the protection effects of sodium para-aminosali cylate(PAS-Na) on concentrations of glutamate (Glu), glutamine (Gln), glycine(Gly) and y-aminobutyric acid (GABA) et al amino acid neurotransmitters in thalamus astrocyte of rats induced by manganese(Mn).Methods (1) The Cells would be used after more than 95% of Cells stained positively for glial fibrillary acidic protein (GFAP) immunocytochemically. The cytotoxicity of Mn and protective effects of PAS-Na about it was observed by CCK8 assay and LDH leakage assay after exposed to MnCl2 (0～1000μmol/L) for 6-48hours and treated with PAS-Na(50-1350μmol/L) for 6-48h. And then, the appropriate and representive levels or time of Mn and PAS-Na were chosen.(2) After exposure to 500μmol/L MnCl2 for 48h, and then treated with 50,150,450 μmol/L PAS-Na for 24h. The concentrations of Glu, Gln, Gly and GABA in rat thalamus were detected by the high performance liquid chromatography (HPLC) ultraviolet detection technique; The concentrations of glutamine synthetase(GS) in thalamus astrocytes was detected by Elisa.Results (1) The cultured astrocytes would be used after more than 95% of the cells stained positively for GFAP immunocytochemically. The cytotoxicity of MnCl2 was detennined by CCK8 assay and LDH release assay. It was found that with inereasing of MnCl2 concentration (0～1000 μmol/L) and time(6-48h), the cell viability deereased and LDH leakage inereased concentration-dePendently. After exposed to 500μmol/L MnC12 for 48h, the cell viability rate decreased to 58.9%. It was suggested that 500μmol/L MnCl2 might be about 50% inhibitory concentrations (IC50). After treated with 50～1350μmol/L PAS-Na for 6-48h, the CCK8 assay and LDH leakage assay were taken. Compared with 500μmol/LMnCl2 group, the cell viability increased and LDH release decreased in 50,150 and 450μmol/L PAS-Na after treated for 24h. However, there was no significant difference between 24h and 48h group at the same treatment concentration.(2) HPLC and ELISA results showed that:compared with the control group, manganese (500μmol/L) 48 hours group thalamus astrocytes Gln and GABA content were decreased, GS activity was decreased, Glu and Gly levels were increased (p<0.05); 500Mn group (500 umol/LMnCl2,48 hours) thalamus astrocytes extracellular Glu and Gly content were higher than the control group, Gln content was higher than the control group (P<0.05), while the GABA content did not change significantly (P> 0.05); Compared with 500Mn group, the intracellular Glu content in 500Mn+450PAS group and the extracellular Glu content in 500Mn+150PAS group,500Mn+450PAS group were decreased, the intracellular Gln content in 500Mn+450PAS group and the extracellular Glu content in 500Mn+50PAS group,500Mn+150PAS group and 500Mn+450PAS group were increased, the intracellular Gly content in 500Mn+150PAS and 500Mn+450PAS group reduced, the intracellular GABA levels in 500Mn+150PAS and 500Mn+450 PAS group were increased (p<0.05).500Mn group GS activity lower than the control group; compared with 500Mn group, GS activity of 500Mn+450 PAS group was increased (p<0.05).Conclusion In vitro, manganese processing will damage primary cultured rat thalamus astrocytes, leading to Glu, Gln, Gly, GABA and GS Activity abnormal changes. PAS-Na has protection effects on changes of primary cultured rats thalamus astrocyte Glu, Gln, Gly, GABA content, GS activity induced by Mn intervention has changed the role of the. manganese treatment resulted in hypothalamic astrocytes toxicity.