反式桂皮醛通过抑制前额皮质IL-1β改善阿尔茨海默病小鼠记忆障碍的作用研究

Study on the Effect of Trans-cinnamaldehyde on Improving Memory Impairment by Inhibiting IL-1βin Prefrontal Cortex of Mice with Alzheimer's Disease

目的探讨反式桂皮醛(Trans-cinnamaldehyde,TCA)对早老素1/2条件性双基因敲除(Presenilin1/2 conditional double knockout,PS cDKO)阿尔茨海默病(Alzheimer's disease,AD)样小鼠的神经保护作用及其机制。方法通过基因鉴定确定小鼠的基因型,将9月龄的PS cDKO小鼠和其同窝野生型对照小鼠随机分为4组:野生型组(wildtype,WT)、野生型+TCA组(WT+TCA)、模型组(PS cDKO,cDKO)和模型+TCA组(cDKO+TCA),每组15只。WT+TCA和cDKO+TCA组的小鼠给予含有TCA(240 ppm)的饲料治疗,WT和cDKO组的小鼠给予普通饲料,共治疗90天,后30天进行行为学测试,测试结束后取材进行分子生物学检测。其中,旷场实验观察TCA对PS cDKO小鼠运动能力的影响;新异物体识别实验观察TCA对PS cDKO小鼠辨识记忆的影响;Y迷宫实验观察TCA对PS cDKO小鼠空间记忆的影响;Western Blot检测TCA对PS cDKO小鼠前额皮质中突触蛋白表达的影响;qRT-PCR检测TCA对PS cDKO小鼠前额皮质中促炎症因子白介素-1β(interleukin-1β,IL-1β)的mRNA水平的影响;ELISA检测TCA对PS cDKO小鼠前额皮层中IL-1β含量的影响。结果TCA对PS cDKO小鼠的运动能力没有影响,可以改善其受损的短时辨识记忆(P<0.05)和空间记忆(P<0.001)。另外,TCA上调PS cDKO小鼠前额皮质中N-甲基-D-天冬氨酸受体(Nmethyl-D-aspartate receptor,NMDAR)的亚基NR1(P<0.05)和钙/钙调蛋白依赖性蛋白激酶Ⅱ alpha(Ca/calmodulin-dependent protein kinases Ⅱ alpha,αCaMKII)的磷酸化水平(P<0.01)的表达,下调IL-1β的mRNA水平(P<0.001)和减少IL-1β的产生(P<0.05)。结论TCA可能通过抑制前额皮质促炎症因子IL-1β和上调突触蛋白的表达发挥对PS cDKO小鼠的神经保护作用。

Objective To explore the neuroprotective effect and mechanism of trans-cinnamaldehyde(TCA)in Presenilin 1/2 conditional double knockout(PS cDKO)mice with Alzheimer's disease(AD).Methods The nine-monthold PS cDKO mice and their litters with determined genotype were randomly divided into four groups:wild type mice group(WT),wild type mice+TCA group(WT+TCA),PS cDKO mice group(cDKO)and PS cDKO mice+TCA group(cDKO+TCA).WT+TCA and cDKO+TCA mice were fed with feed supplemented with TCA(240 ppm),and WT and cDKO mice were treated with normal feed for 60 days,followed by behavioral tests for 30 days.Mice were treated with TCA continuously during the behavioral tests.Then,mice were sacrificed for molecular biological experiments after the behavioral tests at the age of 12 months.Open field test was used to measure the effect of TCA on the movement ability of PS cDKO mice;Novel object recognition task was used to observe the effect of TCA on the recognition memory of PS cDKO mice;Y maze test was used to detect the effect of TCA on spatial memory of PS cDKO mice.Western Blot was used to analyze the effect of TCA on synaptic proteins expressions in the prefrontal cortex of PS cDKO mice;qRT-PCR was used to detect the effect of TCA on the mRNA level of interleukin-1β(IL-1β)in the prefrontal cortex of PS cDKO mice;ELISA was used to measure the effect of TCA on the level of IL-1βin the prefrontal cortex of PS cDKO mice.Results TCA did not affect the movement ability of PS cDKO mice and could improve their impaired short-term recognition memory(P<0.05)and spatial memory(P<0.001).Besides,TCA up-regulated the expression of NR1(P<0.05)and p-αCaMKII(P<0.01)in the prefrontal cortex of PS cDKO mice.Meanwhile,TCA down-regulated the mRNA level of IL-1β(P<0.001)and decreased the production of IL-1β(P<0.05).Conclusion TCA may exert neuroprotective effects on PS cDKO mice by inhibiting the expression of pro-inflammatory factor IL-1βand up-regulating the expression of synaptic proteins.