RESUMO
Objective To explore the behavior characteristics ofamyloid precursor protein / tau protein / presenilin-1 (APP/Tau/PS1) transgenic mice in different months of age and study the progress of inflammation and the changes of autophagy level in brain of these APP/Tau/PS1 Alzheimer's disease(AD) mice.Methods Four-month-old wild-type (WT) mice (B6:129SF2/J) and Tau/APP/PS1 transgenic mice at 2,4,6,8 and 12 months old (n=8) were chosen in our study.Morris water maze was used to detect the spatial learning and memory abilities ofAPP/Tau/PS1 AD mice.After the paraffin section,immunohistochemical fluorescence technology was used to detect the expression and distribution of glial fibrillary acidic protein (GFAP) in the brain of mice in the above 6 groups.The expression changes of GFAP,CD45 (inflammation marker) and LC3 (autophagy marker) in the hippocampal tissues of 6 groups were detected by Western blotting.Results In the morris water maze test,the escape latency increased obviously following the increasing of months:the latency of 6 months old mice was significantly prolonged as compared with that of 2 months old mice (P＜0.05),which was further significantly increased in 12-month-old mice (P＜0.05).In the exploring experiment,with the increasing of months,the times of crossing the original table in mice showed a trend of decline,time ofresidencing in the original platform quadrant was significantly reduced.As compared with that in the WT mice,the GFAP expression in the hippocampus of 8 and 12 months old AD mice was significantly increased (P＜0.05); meanwhile,the GFAP expression in 8-month-old mice was also significantly higher than that in 2 months old AD mice (P＜0.05).The CD45 expression in 6 months old AD mice was obviously increased as compared with that of WT mice (P＜0.05).As to the level of LC3-Ⅱ/Lc-Ⅰ,there was a significant increase in 2 months old AD mice as compared with WT mice (P＜0.05),which was further increased in 4 months old AD mice (P＜0.05),but decreased in 6 and 8 months old AD mice.Conclusion With the gradually loss of the leaming and memory abilities,inflammatory reaction is significantly increased,and the autophagy level increases at first,and then,decreases in the brain ofAPP/Tau/PS1 AD mice.
RESUMO
Objective To identify the genotype of the APP/tau/PS1 triple transgenic Alzheimer's disease (AD) mice,and investigate the pathological changes of tau protein in the pathogenic process.Methods Using specific primers of PS1,APP,tau gene,the genotypes of the triple transgenic AD mice were identified.Expression of tau protein in hippocampal tissue of mouse model aged 2,4,8 month was detected by immunohistochemistry.The expression of tau and its hyperphosphorylation in different sites in the hippocampal tissue and different month old mice was detected by Western blotting.Results PCR amplification fragment of 960 bp,530 bp and 400 bp of transgenic mouse genome were the expected size of APP,PS1,tau,respectively.Expression of tau in hippocampal CA3 region was increased obviously in the 8 month old mice.Compared with the normal wild-type mice,the expressions of tau and phosphorylation of pS262,pS404 and pS202 were increased significantly in hippocampus tissue of the transgenic mice (P＜0.01).Expression of tau were significantly higher in 8-and 12-monthsold mice than in 2 months-old mice (P ＜ 0.01).Phosphorylation level of pS404 and Ps202 was significantly increased since 2-months-old in transgenic mouse compared to the wild type mouse (P＜0.01),and in 8-monthold mice,there was also a significant increase as compared to that in 2 month-old mice (P＜0.01).As to the phosphorylation level of pSs262,the significant increase did not appear until 12 months old in transgenic mouse as compared to the wild type mouse (P＜0.01).Conclusions The triple transgenic mice can stably express the APP/tau/PS1 gene.The transgenic animals can be a useful model with the pathological features of tau of AD.The phosphorylation level of tau in different site increases in different time,which will provide useful research reference in Alzheimer's disease pathology and medication research.