异丙酚对β-淀粉样蛋白诱导大鼠皮层神经元损伤的影响

Effects of propofol on beta-amyloid protein-induced injury to cultured rat cortical neurons

目的探讨异丙酚对β-淀粉样蛋白（β-AP）诱导大鼠皮层神经元损伤的影响。方法孕18dSD大鼠，体外分离皮层神经元，5×10^4个／孔，每孔200m接种于96孔培养板上，培养7d。实验一：取15孔神经元随机分为5组（n=3）：对照组；损伤组；异丙酚预防给药I组加入β-AP25μmol／L前24h加入异丙酚50μmol／L，再孵育24h；异丙酚预防给药Ⅱ组同时加入异丙酚50μmol，L和8-AP25μmol／L，孵育24h；异丙酚治疗给药组加入β-AP25／μmol／L后6h，加入异丙酚50μmol／L，再孵育18h。实验二：取18孔神经元随机分为6组（n=3）：对照组；损伤组；脂肪乳剂组加入β-AP25μmol／L后6h，加入等容量10％脂肪乳剂，再孵育18h；不同浓度异丙酚组加入β-AP25／μmol／L后6h，分别加入异丙酚1、10、50μmol／L，再孵育18h。测定神经元乳酸脱氢酶（LDH）释放量和神经元活力。采用TUNEL法、Hoechst33342染色观察细胞凋亡情况，计算细胞凋亡率。结果实验一：与损伤组比较，异丙酚预防给药组LDH释放量差异无统计学意义（P〉0．05），异丙酚治疗给药组神经元LDH释放量减少（P〈0．05）。实验二：与损伤组比较，异丙酚50／μmol／L组神经元LDH释放量减少，神经元活力升高，细胞凋亡率降低（P〈0．05）。结论异丙酚50μmol／L治疗性给药可减轻β-淀粉样蛋白诱导大鼠皮层神经元损伤，预防性给药对其无影响。

Objective To investigate the effects of propofol on β-amyloid protein （β-AP）-induced injury to cultured rat cortical neurons. Methods Eighteen days pregnant SD rats were anesthetized with ether. The fetal rats were obtained under sterile condition and decapitated. Cortices were then dissected under dissecting microscope. Cortical neurons were isolated according to the method described by Velly LJ et al and cultured for 7 days. There were 5 × 10^4 neurons in each well （200 μl）. The experiment included 2 parts. In part Ⅰ 15 wells of neurons were randomly divided into 5 groups （ n = 3 each） ： group Ⅰ control （C） ; groupⅡ β-AP 25/μmol/L; group m and Ⅳ 2 propofol pretreatment groups （PP1 , PP2 ） and group V propofol treatment （PT）. In group PP1 propofol 50 μmol/L was added to the culture medium 24 h before the addition of β-AP 25 μmol/L and the neurons were incubated for another 24 h. In group PPz propofol 50 μmol/L and β-AP 25 μmol/L were added to the culture medium simultaneously and the neurons were then incubated for 24 h. In group PT propofol 50μmol/L was added to the culture medium at 6 h after the addition of β-AP 25μmol/L and the neurons were incubated for another 18 h. In part Ⅱ 18 wells of neurons were randomly divided into 6 groups （ n = 3 each） ： group Ⅰ control （C） ; group Ⅱ β-AP 25μmol/L; group Ⅲ intralipid; group Ⅳ, Ⅴ , and Ⅵ 3 propofol treatment groups （P1, Pl0, P50 ）. In intralipid group equal volume of 10% intralipid was added to the culture medium at 6 h after β-AP 25 μmol/L and the neurons were then incubated for another 18 h. In group Ⅳ-Ⅵpropofol 1, 10 and 50μmol/L were added at 6 h after β-AP 25 μmol/L respectively and the neurons were incubated for another 18 h. The amount of lactic dehydrogenase （LDH） released was measured. Neuronal viability was assessed by MTT assay. The neuronal apoptosis was detected using Hoechst33342 staining and TUNEL technique, and the apoptosis rate was calculated. Results In part Ⅰ there was no significant difference in the amount of LDH released between group Ⅱ （β-AP） and the 2 propofol pretreatment groups （ Ⅲ, Ⅳ ）. The amount of LDH released was significantly lower in group Ⅴ （propofol treatment） than in group β-AP （ Ⅱ ）. In part Ⅱ the amount of LDH released was significantly lower, neuronal viability higher and the apoptosis rate was lower in group P50 than in group 11 （β-AP） . Conclusion Propofol 50 μnol/L given after β-AP can attenuate β-AP induced injury to cultured rat cortical neurons while prophylactic administration of propofol can＇t.