银杏叶提取物对低氧复氧、H_2O_2和谷氨酸损伤时谷氨酸引起的大鼠星形胶质细胞[Ca^(2+)]_i变化的影响(英文)

Effects of Gingko biloba extract on glutamate-induc ed [Ca^(2+)]_i changes in cultured cortical astrocytes after hypox ia/reoxygenation, H_2O_2 or L-glutamate injury

目的 研究银杏叶提取物对低氧复氧、H2O2和L 谷氨酸损伤时谷氨酸升高大鼠星形胶质细胞[Ca2+]i的影响。方法 钙荧光探针Fluo 3/AM标记胞浆内游离钙离子,激光扫描共聚焦显微镜测定[Ca2+]i的变化。结果 在低氧复氧、H2O2以及高浓度的L 谷氨酸损伤后,外源性谷氨酸(27μmol·L-1)均不能引起培养乳大鼠星形胶质细胞正常的[Ca2+]i升高,反而使[Ca2+]i分别降低(3.3±1.6)%,(81±11)%和(81±7)%;损伤前预先给予GbE(10 mg·L-1)不能明显改善星形胶质细胞的谷氨酸反应,但预先给予GbE(100mg·L-1)后,27μmol·L-1谷氨酸可使损伤的星形胶质细胞[Ca2+]i分别升高(135±98)%,(117±93)%和(89±36)%。结论低氧复氧、H2O2以及高浓 度的L 谷氨酸均能损伤星形胶质细胞的谷氨酸反应,影响神经细胞与胶质细胞的双向交流。GbE能明显逆转不同损 伤后谷氨酸诱导星形胶质细胞[Ca2+]i的异常变化,使星形胶质细胞在不同损伤时能维持正常功能,该作用可能与 GbE的脑保护作用有关。

Aim To investigate glutamate-induced [Ca 2+] i changes in cultured rat neonatal cortical astrocytes after hypoxia/reoxygenation, H 2O 2 or high concentration of L-glu tamate injury. In the meantime, the effects of Gingko biloba extract (Gb E) were examined. Methods [Ca 2+] i changes in astrocytes were monito red by laser scanning confocal microscopy with the Ca 2+ sensitive fluoresc ent probe fluo-3. Results After astrocytes were impaired by hypoxia/reoxygenation , H 2O 2 (50 μmol·L -1) or L-glutamate (0.25 mm ol·L -1), the exogenous glutamate (27 μmol·L -1) could not in duce increase of [Ca 2+] i, but decrease by (3.3±1.6)%, (81±11)% and (81±7)%, respectively. Pretreatment with GbE (10 mg·L -1) co uld not improve injured astrocytic glutamate response. But after pretreatment wi th GbE (100 mg·L -1), glutamate-induced [Ca 2+] i ele vation of astrocytes after hypoxia/reoxygenation, H 2O 2 or high c oncentration of L-glutamate injury were (135±98)%, (117±93)% and (89±36) %, respectively. Nimodipine (1.6 mg·L -1) could also reverse the abno rmal response of astrocytes after different injury. Conclusion Hypoxia/reoxygenation, H 2O 2 and high concentration of L-glutamate impaired astrocytes′ response to exogenous L-glutamate, and then bidirectional communication between astrocytes and ne urons could not take place. GbE could improve the abnormal responses and mai ntain the normal function of astroglical network. These effects support that G bE has potential beneficial actions against brain injury.