Effect of β-catenin RNAi Interference on Signal Mechanism of Huangjingwan in Treating Learning and Memory Impairment Mice / 中国实验方剂学杂志

ABSTRACT

Objective:To treat mice with Alzheimer's disease （AD） with β-catenin RNA interference （RNAi） Huangjingwan （HW）， so as to explore the neuroprotective signal mechanism of its prevention and treatment of AD. Method:A total of 81 male Kunming mice were randomly divided into normal control group， sham model control group， AD model group， Donepezil group， HW+scrambled group， HW+RNAi group， HW group， with 8 mice in each of donepezil group and HW group， and 13 mice in each of other groups. The AD models were established through injection with D-galactose and scopolamine in the last 5 groups for 5 consecutive weeks. On the 1st day of the 4th week after modeling， 0.75 μL PEI-LMW/β-catenin siRNAs nano-complex was injected into the right lateral ventricle of each mouse in for one time to treat with β-catenin RNAi in mice brains of the HW+RNAi group. The 0.75 μL complex was injected into the right lateral ventricle of each mouse for one time as for β-catenin interference control of the HW+scrambled group. The 0.75 μL normal saline was injected into the right lateral ventricle of each mouse in one time of the sham control group. Two weeks after intracerebroventricular injection， β-catenin RNAi was confirmed to be successful， and Donepezil （6.5×10-4 g·kg-1） was intragastrically administered to each mouse of donepezil group. HW （2.5 g·kg-1） was intragastrically administered to each mouse of HW group， HW+RNAi group and HW+scrambled group. Normal saline （0.5 mL·d-1） was intragastrically administered to each mouse of the sham control group. All gastric perfusion lasted for 4 weeks. At the end of gavage， the difference in learning and memory ability of mice was evaluated by platform jumping test. Nissl staining was used to count the number of neurons in s1Tr area of cerebral cortex and CA1 and CA3 areas of hippocampus of each mouse in each group. The mRNA expressions of Wnt1， DVL2， GSK-3β， β-catenin and CyclinD1 in mice brain of each group were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. Western blot was used to detect the expressions of Wnt1， DVL2， GSK-3β， β-catenin and CyclinD1 in mice brain of each group. Result:The expression of β-catenin could be significantly inhibited through the injection with PEI-LMW/β-catenin siRNAs nano-complex into the lateral ventricle of AD mice， and nearly no β-catenin expression could be detected， which successfully achieved gene silencing. Compared with the normal control group， mice in AD model group showed that the learning and memory performance decreased significantly， the number of jumping errors increased （P<0.01）， the number of neurons in S1Tr area of cerebral cortex and CA1， CA3 areas of hippocampus decreased significantly （P<0.01）， the mRNA and protein expressions of Wnt1， DVL2， β-catenin， CyclinD1 in brain decreased significantly （P<0.01）， while the mRNA and protein expressions of GSK-3β increased significantly （P<0.01）. Compared with the AD model group， mice in HW group showed that the learning and memory performance increased significantly， the number of jumping errors decreased， the number of neurons in S1Tr area of cerebral cortex and CA1， CA3 areas of hippocampus increased significantly， the mRNA and protein expressions of Wnt1， DVL2， β-catenin， CyclinD1 in brain increased significantly， while the mRNA and protein expression of GSK-3β decreased significantly （P<0.01）. Compared with the HW group， mice in HW+RNAi group showed that the learning and memory performance decreased significantly， the number of jumping errors increased significantly （P<0.01）， the number of neurons in S1Tr area of cerebral cortex and CA1， CA3 areas of hippocampus decreased significantly （P<0.01）， there was no significant change in mRNA and protein expressions of Wnt1， DVL2， GSK-3β in the brain， and the mRNA and protein expressions of β-catenin， CyclinD1 decreased significantly （P<0.01）. Conclusion:HW can treat and prevent AD by activating Wnt/β-catenin signal pathway.