人参皂苷Rg_1对大鼠脑片AD模型磷酸化Tau蛋白及NMDA受体亚单位NR1,NR2B表达的影响

Effect of ginsenoside Rg1 on expressions of phosphory protein Tau and N-methyl-D-aspartate receptor subunits NR1 and NR2B in rat brain slice model of Alzheimer′s disease

目的:观察人参皂苷Rg1对大鼠脑片AD模型磷酸化Tau蛋白(Phosphory protein Tau,P-Tau)及N-甲基-D-门冬氨酸受体亚单位1(N-methyl-D-aspartate receptor subunit 1,NR1)、亚单位2B(N-methyl-D-aspartate receptor subunit 2B,NR2B)的表达影响。方法:将5周龄雄性Wistar大鼠脑片(含皮层和海马)随机分为5组:空白对照组、模型组和低、中、高剂量人参皂苷Rg1组,每组10张脑片,脑片放置盛有人工脑脊液(artificial cerebrospinal fluid,ACSF)的6孔板中培养,温度(32.0±0.5)℃,整个过程ACSF中持续通入混合氧气(95%O2+5%CO2)。人参皂苷Rg1各组ACSF中首先加入人参皂苷Rg1(60,120,240μmol.L-1)作用2 h,然后模型组和人参皂苷Rg1各组ACSF中分别加入冈田酸(okadaic acid,OA)1μmol.L-1作用3 h,空白对照组不加任何处理因素。采用免疫组织化学、图像分析技术等方法,检测皮层和海马P-Tau,NR1,NR2B表达水平。结果:与对照组比较,模型组大鼠脑片P-Tau的表达增加(P<0.05或P<0.01),NR1,NR2B的表达降低(P<0.01);人参皂苷Rg1各组与模型组比较,大鼠脑片P-Tau的表达降低(P<0.01或P<0.05),NR1,NR2B的表达增加(P<0.01或P<0.05),其中以高剂量人参皂苷Rg1组效果最佳。结论:人参皂苷Rg1可以降低大鼠脑片AD模型P-Tau表达水平,并能上调学习记忆相关蛋白NR1,NR2B的表达,以此途径发挥抗痴呆作用。

Objective： To investigate the effect of ginsenoside Rg1 on the expressions of phosphory protein Tau（P-Tau）,N-methyl-D-aspartate receptor subunit 1（NR1） and N-methyl-D-aspartate receptor subunit 2B（NR2B） in rat brain slice model of Alzheimer′s disease.Method： Brains of 5-week-old Wistar rats were cut into slices which were 400 μm thick.These brain slices were randomly divided into normal control group,untreated group,low-dose ginsenoside Rg1 group,medium-dose ginsenoside Rg1 group and high-dose ginsenoside Rg1 group,with 10 slices in each group.All brain slices were cultured with artificial cerebrospinal fluid（ACSF） that was aerated via polyethylene tubing attached to a source of 95% O2,5% CO2 at（32.0±0.5） ℃.And brain slices in the ginsenoside R1 groups were administrated with the ginsenoside Rg1（60,120 and 240 μmol·L-1respectively） in ACSF for 2 h firstly.Then okadaic acid（OA） was administrated into ACSF of untreated group and ginsenoside Rg1 groups separately for 3 h to induce Tau phosphorylation to prepare AD models.The concentration of OA in each group was 1 μmol·L-1.And there was no any intervention for the brain slices in the normal control group.The expressions of P-Tau,NR1 and NR2B in brain slices in each group were determined by immunohistochemical method,and the results were analyzed by image acquisition and analysis system.Result： Compared with the normal control group,the expression of P-Tau was significantly increased（P〈0.05 or P〈0.01） and the expressions of NR1 and NR2B were decreased（P〈0.01） in untreated group.Compared with the untreated group,the expression of P-Tau was significantly decreased（P〈0.01 or P〈0.05） and the expressions of NR1 and NR2B were increased（P〈0.01 or P〈0.05） in ginsenoside Rg1 groups,especially in high-dose ginsenoside Rg1 group.Conclusion： Ginsenoside Rg1 can play the role of anti-dementia by inhibiting the expression of P-Tau so as to slow the formation of neurofibrillary tangles and increasing the expression of NR1 and NR2B so as to improve learning and memory abilities in rat brain slice model of Alzheimer′s disease.