丙泊酚对大鼠脑片不同性质损伤的影响

目的　考察丙泊酚对能量代谢障碍、兴奋性氨基酸、氧自由基 3种脑片损伤模型的作用效果。方法　建立大鼠皮层和海马脑片的缺氧缺糖、谷氨酸、过氧化氢损伤模型 ,每个损伤实验又分别设立对照组、损伤组、丙泊酚加损伤组 (浓度为 5、5 0及 10 0 μmol/L) ,每组大鼠 4例。采用新鲜脑片TTC染色比色法 ,测定各组脑片TTC染色的变化 ,比较丙泊酚对不同性质脑损伤作用效果。结果　和对照组比较 ,缺氧缺糖、谷氨酸和过氧化氢明显降低皮层和海马脑片TTC染色吸光度值 (A490 )。和损伤组比较 ,低、中剂量丙泊酚对缺氧缺糖和谷氨酸损伤所致A490 降低无作用 ,大剂量 (10 0 μmol/L)加重脑片TTC染色A490 降低 (P <0 0 1)。 5 μmol/L丙泊酚明显抑制过氧化氢损伤所致皮层和海马脑片TTC染色A490 降低 (P <0 0 1) ,大剂量时该作用消失 (P >0 0 5 )。结论　低剂量 (5 μmol/L)丙泊酚对大鼠皮层和海马脑片过氧化氢损伤具有保护作用 ,对脑片缺氧缺糖和谷氨酸损伤无保护作用 ,大剂量 (10 0 μmol/L)丙泊酚加重大鼠皮层和海马脑片缺氧缺糖和谷氨酸损伤。

The influences of propofol on different kinds of brain injuries in rat brain slices

OBJECTIVE: To investigate the effects of propofol on the three kinds of brain injuries induced by metabolic disorder, neurotoxicity of excitatory amino acid, and oxygen-derived free radicals in rat cerebral cortical and hippocampal slices. METHODS: Slices of rat cerebral cortex and hippocampus were made and incubated in normal artificial cerebrospinal fluid (nACSF). Then the rat cerebral cortical and hippocampal slices were divided into 2 categories: propofol group, the slices in which were co-incubated with 5, 50, or 100 micro mol/L propofol for 3 hours, and 3 experimental injury groups. Each experimental injury group was further subdivided into 3 subgroups including the slices of 4 rats. Two hours after normal incubation the slices were co-incubated with 2,3,5-triphenyltetrazolium chloride (TTC). Formazan, the red crystal product were extracted, and ELISA reader was used to read the absorbance at 490 nm (A(490)) so as to quantitatively evaluate the degree of injury. RESULTS: The values of A(490) of the slices co-incubated with propofol of different concentrations were not significantly different. Compared with those of the control subgroups, the values A490 were significantly decreased in the cerebral cortical and hippocampus slices damaged by OGD, glutamate, and H(2)O(2) injuries (all P < 0.01). The values of A(490) in the subgroups of low and middle concentrations (5 and 50 micro mol/L) of propofol plus OGD or glutamate injury were not significantly different from those of the subgroups of OGD or glutamate injury alone, both in cerebral cortical and hippocampal slices. However, the values of A(490) in the subgroups of high concentration of propofol (100 micro mol/L) plus OGD or glutamate injury was further decreased (P < 0.01). The values of A(490) in the subgroups of low and middle concentrations of propofol plus H(2)O(2) injury were significantly higher than those of the injury subgroup (all P < 0.01), however, however, the values of A490 in the high concentration propofol plus H(2)O(2) injury subgroup were significantly lower than those of the control group (all P < 0.01), even lower than that of the subgroup of H(2)O(2) injury alone. CONCLUSION: Propofol has a neuroprotective effect against hydrogen peroxide injury at low and middle concentrations. Propofol of low and middle concentrations does not improve the decrease of the value of A(490). however, propofol of high concentration augments the oxygen-glucose deprivation and glutamate injuries both in the rat cerebral cortical slices and hippocampal slices.