丙泊酚对N-甲基-D-天冬氨酸所致PC12细胞损伤的保护作用

目的　探讨静脉麻醉药丙泊酚 (PPF)脑保护作用的可能机制。方法　乳酸脱氢酶 (LDH)法及MTT比色法判断细胞损伤程度及细胞存活率 ,Fura 2 /AM荧光标记法测定细胞内Ca2 + 浓度 ( Ca2 + ]i)的变化 ,分光光度法测定细胞一氧化氮合酶 (NOS)活性。结果　N 甲基 D 天冬氨酸 (NMDA) 3 0 0 μmol·L-1处理4h可明显导致PC1 2细胞的损伤 ,表现为LDH释放量明显增加 ,吸光度值A570nm明显降低 ,细胞存活率降低 ,同时 Ca2 + ]i 和NOS活性则明显增加。PPF6.2 5 ,2 5 ,1 0 0 ,40 0 μmol·L-1与NMDA同时处理PC1 2细胞则使LDH释放量显著降低 ,细胞存活率增加。PPF 1 2 .5和 1 2 5 μmol·L-1可显著降低NMDA诱导的Ca2 + ]i 水平及NOS活性的提高。结论　PPF对NMDA所致的PC1 2细胞损伤有明显的保护作用 ,其机制可能与其抑制NMDA受体的功能 ,降低 Ca2 + ]i,减弱Ca2 + 超载 ,并降低NMDA诱导的NOS活性增加有关。提示PPF可能是通过抑制NMDA受体 Ca2 + NOS通路的功能而产生细胞保护效应

Protection of propofol on cultured PC12 cells impaired by N-methyl-D-aspartate

AIM To evaluate the possible mechanism of the protective effect on brain of propofol. METHODS Cellular viability was detected using lactic dehydrogenaseLDH) assay and MTT assay. Meanwhile, the the intracellular Ca²⁺ concentration(［Ca²⁺］_i) was detected by Fura- 2/AM fluorescence method and the activity of nitric oxide synthase(NOS) was measured with ultraviolet spectrophotometer. RESULTS After exposing to N-methyl-D-aspartate(NMDA) 300 μmol·L^-1 for 4 h, the release of LDH in PC12 cells was increased and the values of A_{570 nm} (MTT assay) decreased, which indicated that NMDA induced impairment in PC12 cells, whereas in the presence of propofol 6.25, 25, 100, 400 μmol·L^-1 for 4 h, the LDH was decreased and the values of A_{570 nm} increased. Furthermore, exposing to NMDA 300 μmol·L^-1 for 4 h, ［Ca²⁺］_i and the activity of NOS in PC12 cells raised significantly, while treatment with propofol 12.5, 125 μmol·L^-1 simultaneously decreased the ［Ca²⁺］_i and the activity of NOS, compared with NMDA group. CONCLUSION Propofol can attenuate the NMDA induced impairment of PC12 cells, decrease the Ca²⁺ overloading and the activity of NOS in PC12 cells treated with NMDA. Effects of propofol on the overload of the ［Ca²⁺］ _i and the inhibition of NOS in PC12 cells may be one of the mechanisms for this protective action.