| Objective:This study takes tau transgenic mice as the research object to explore the effect of Cannabinoid(CBD)on the behavior,pathology and protein expression of tau transgenic mice and the therapeutic effect and treatment principle of CBD on ad like symptoms,and to provide molecular targets for clinical development of CBD for Alzheimer(AD)treatment,which has important scientific significance and clinical application value.Methods:18 male tau transgenic mice of the same week age were randomly divided into two groups to construct the model:one group was tau genome transfer(contrl group)(simulated operation was performed by intraperitoneal injection of 0.1 ml/d/10g 0.9%sodium chloride solution),and the other group was CBD treatment group(0.1 ml/d/10g 50 mg/kg · D 19 c57b1/6 mice of the same sex and same month were divided into two groups:one group was used as the normal control group(WT group)(simulated operation was performed by intraperitoneal injection of 0.1 ml/d/10g 0.9%sodium chloride solution),and the other group was drug control group(CBD+wt group)(0.1 ml/d/10g 50 mg/kg·D CBD injection was used for intraperitoneal injection).The expression levels of NeuN,at8 and Ibal in mice brain were detected by immunofluorescence staining,chat was detected by DAB staining,and BACE1 and PSD95 protein expression were detected by Western blot.Results:1.In the hidden platform test,the diurnal effect of escape latency in the four groups showed by Morris water maze test was significant(p<0.05),and there was also difference among the four groups(p<0.05).From day 3 to day 5,the escape latency of mice in Con group was significantly longer than that in WT group(p<0.05),while that in CBD group was significantly shorter than that in Con group(p<0.05).In the platform exploration experiment,compared with WT group,the frequency of crossing the target platform and the percentage of time in the target quadrant of mice in Con group were significantly decreased(p<0.05),while compared with Con group,the frequency of crossing the target platform and the percentage of time in the target quadrant of mice in CBD group were significantly increased(p<0.05).In open field experiment,compared with WT group,the exploration time of mice in Con group was significantly reduced(p<0.05);compared with Con group,the exploration time of mice in CBD group was significantly increased(p<0.05).Compared with WT group,the average speed and exploration journey of mice in Con group were significantly reduced(p<0.05);compared with Con group,the average speed and exploration journey of mice in CBD group were significantly increased(p<0.05).2.Immunofluorescence staining was used to detect the hyperphosphorylation of tau protein.The results showed that the staining area of at8 in Con group was significantly larger than that in WT group(p<0.05),and that in CBD group was significantly lower than that in Con group(p<0.05).Western blot was used to detect the expression level of BACE1 to determine the effect of CBD on a β.The results showed that the expression level of BACE1 protein in Con group was significantly lower than that in WT group(p<0.05),while the expression level of BACE1 protein in CBD group was significantly higher than that in Con group(p<0.05).3.In order to explore whether the transgenic mice after CBD treatment can effectively improve the degree of apoptosis,immunofluorescence staining was used to stain NeuN labeled neurons.The results showed that compared with WT group,the NeuN staining area of mice in Con group was significantly reduced(p<0.05);compared with Con group,the NeuN staining area of mice in CBD group was higher and denser(p<0.05).4.In this study,specific binding staining of microglia marker Ibal was used to detect the brain inflammation of tau transgenic mice treated with CBD.The results showed that compared with WT mice,the activation of microglia in the brain of Con mice was significantly increased(p<0.05);compared with Con mice,the activation of microglia in transgenic CBD mice was not significantly increased(p<0.05).5.DAB staining was used to detect the expression of ChAT.Compared with WT group,the chat density of brain pathological sections in Con group was significantly decreased(p<0.05),and compared with Con group,the chat density in CBD group was significantly increased(p<0.05).Western blot was used to detect the expression of PSD95.The results showed that the expression level of PSD95 protein in Con group was significantly lower than that in WT group(p<0.05),and the expression level of PSD95 protein in CBD group was significantly higher than that in Con group(p<0.05).Conclusion:In this study,CBD can reduce the learning,memory and cognitive decline of tau transgenic mice,reduce the abnormal phosphorylation of tau protein and reduce the damage of hippocampal neurons.The mechanism may be related to multiple signal pathways mediated by multiple gene interactions.The results of this study are to explore the therapeutic effect of CBD on ad from the perspective of molecular mechanism,which will provide molecular targets for clinical development of CBD for AD treatment,which has important scientific and clinical application value. |
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