海人酸活化的小胶质细胞H_2O_2、NO的分泌对海马神经元谷氨酸含量的影响

目的:初步探讨海人酸(KA)活化培养的新生SD大鼠小胶质细胞(MG)及其分泌的一氧化氮/过氧化氢(NO/H2O2)、海马神经元、谷氨酸(Glu)之间的相互关系。方法:以KA作为MG的激活剂,以一氧化氮合成酶(NOS)的抑制剂氨基胍(AG)或过氧化氢的水解酶(CAT)作为工具药,先检测原代分离纯化培养的MG在KA激活后及工具药作用后各组条件培养液中NO和H2O2含量的变化,再用各组小胶质细胞条件培养液孵育离体海马神经元,观察其对神经元内Glu表达的影响。结果:KA作用后各组条件培养液中NO和H2O2含量明显升高,经AG或CAT处理后各组条件培养液中NO和H2O2含量显著降低;海马神经元的Glu免疫反应性KA组较对照组明显增强,在AG+KA组和CAT+KA组较KA组明显减弱。结论:活化的MG可能通过氧化损伤机制作为参与癫痫发作一个重要环节,提示采取抑制小胶质细胞活化、减少氧化损伤也可能是癫痫防治研究的一个重要方向。

Effects of Increased Secretion of H2O2 and NO in Kainic Acid Activated Microglia on the Content of Glutamate in Rat Hippocampal Neurons

Objective:To explore the relationship among activated microglia,NO/H2O2,hippocampal neurons and glutamate(Glu)and to provide new research data for the mechanism of epilepsy and its controlling strategies.Methods:Microglia and hippocampal neurons were cultured and kainic acid(KA)was chosen to activate microglia.Aminoguanidine(AG),a NOS inhibitor,and hydrogen peroxide hydrolase(CAT)were selected as medical intervention tools.Firstly,the content of NO and H2O2 in the conditioned medium of primary cultured microglia induced by KA were detected,and then primary cultured hippocampal neurons were incubated with different microglial conditioned medium to observe the expression of Glu by immunocytochemical staining.Results:Con-centrations of NO and H2O2 in microglial conditioned medium of each group were higher than those of the medium before the stimulating factors were removed.After treated with CAT or AG,NO and H2O2 level in the KA conditioned medium were significant decreased and the immunostaining of Glu in hippocampal neurons of KA group was stronger than that of the control group,and it was significantly weakened in the AG + KA group and the CAT + KA group when compared to that of KA group.Conclusion:Activated microglia may be involved in epilepsy by oxidative damage mechanisms.Therefore,it is an important strategy against epilepsy by inhibiting microglia activation and reducing oxidative damage.