The Di-Huang-Yi-Zhi Protects APP/PS1 Mice From Oxidative Stress Nerve Damage By Regulating Nrf2/ARE Signal Transduction Through Histone Acetylation

Objective:Using APP/PS1 genetically modified mice as a model of Alzheimer’s disease,objective to study the neuroprotective effect of Di-Huang-Yi-Zhi prescription（DHYZ）on APP/PS1 mice and its possible mechanism,from the perspective of learning and memory ability,the ultrastructure of neurons and synapses,apoptosis,Nrf2/ARE signaling path and histone acetylation.Method:1.Three-month-old male APP/PS1 double genetically modified AD mice were selected for 100 mice,randomly divided into 5 groups,namely Model group,Donepezil group（0.83mg/kg/d）and DHYZ low,medium and high dose group（dip powder dose is 1.560,3.121,6.241g/kg/d）.There were also 20 non-GMO mice（c57）with the same background as a Normal control group.The Normal and Model groups were given an equal amount of dd H₂O for 12 weeks of gastric intervention.The morris water maze tested the mice’s learning and memory abilities in weeks 6 and 12.2.In weeks 6 and 12,we took 3 mice’s hippocampal tissue from each group,the ultrastructural changes of hippocampal neurons and synapses were detected by transmission electron microscope.3.In weeks 12,we took mice’s hippocampal tissue from,TUNEL staining method to test apoptosis;Caspase-3 was measured by Spectrophotometer;Detection of ROS production in mouse hippocampus by DCFH-DA fluorescent probe.4.In weeks 12,we took mice’s Hippocampal tissue,immunosocipic chemistry and Western blot method to detect the expression of Nrf2 and its target genes HO-1,NQO1,GCLC.5.In weeks 12,we took mice’s hippocampal tissue,Western blot to test histoprotein H3and H4 expression and acetylation,the activity of HATs and HDACs was detected by chemical colorimetry.Result:1.Effect of the DHYZ on the learning and memory ability of APP/PS1 miceIn weeks 6 and 12,compared with the Normal group,the total distance of the AD group and the escape incubation period were extended,the number of times the platform was crossed and the time spent in the original platform quadrant was shortened,and there were obvious cognitive impairments.Compared with the AD group,the total distance and incubation period of Donepezil group and DHYZ group were shortened to varying degrees,and the number of crossing platforms and the length of stay in the first quadrant were extended to varying degrees.The effect of DHYZ（M）group was better than that of DHYZ（L）and DHYZ（H）group.2.Effect of the DHYZ on the ultrastructure of neurons and synapses in hippocampus of APP/PS1 miceIn weeks 6 and 12,compared with the Normal group,the AD group cell nucleation,nuclear membrane is not clear,mitochondrial swelling,the number of synapses is less（P<0.01）.Compared with the AD group,the Donepezil group and the DHYZ group mice had clearer neural membranes,lighter mitochondrial swelling,and more synapses（P<0.05）.3.Effect of the DHYZ on apoptosis induced by oxidative stressIn weeks 12,ROS was green fluorescent,TUNEL staining Normal group cell morphology is normal,cell nuclei are clear.Compared with the Normal group,the AD group ROS showed an increase（P<0.01）,apoptosis cells increased significantly（P<0.01）,and Caspase-3 activity increased（P<0.01）.Compared with the AD group,the DHYZ group can reduce the content of ROS to varying degrees（P<0.01）,reduce apoptosis（P<0.05）,and reduce Caspase-3 active（P<0.05）,but higher than the Donepezil group（P<0.05）.4.Effect of the DHYZ on Nrf2 and its target geneIn weeks 12,there was no significant difference in the expression of AD group Nrf2and its downstream target genes HO-1,NQO1,and GCLC compared to the Normal group.Compared with the AD group,the DHYZ can adjust the expression of Nrf2 and its downstream target genes HO-1,NQO1 and GCLC tovarying degrees,with the DHYZ（M）and DHYZ（H）groups performing better.However,it is lower than the Donepezil group（P<0.01）.5.Effect of the DHYZ on histone acetylationIn weeks 12,compared with the Normal group,the HATs activity of AD group was not significantly different,HDACs activity increased significantly（P<0.01）,histoprotein H3,H4 acetylation no significant difference.Compared with the AD group,the Donepezil group and the DHYZ can increase the activity of HATs（P<0.01）and reduce the activity of HDACs（P<0.01）,promotes histone H3,H4 acetylation.Conclusion:The DHYZ has a protective effect on the learning and memory ability of APP/PS1mice,the ultrastructure of neurons and synapses,and apoptosis induced by oxidative stress,and its mechanism may be associated with regulating Nrf2/ARE antioxidant stress signaling path,raising the expression of antioxidant enzymes such as HO-1,NQO1 and GCLC,reducing ROS production and Caspase-3 activity.