Objective To observe the effects of Xixin Decoction on the blood-brain barrier permeability and the expressions of P-glycoprotein(P-gp),cannabinoid receptor 1(CB1)and cannabinoid receptor 2(CB2)in hippocampal tissue of rapidly aging mice(SAMP8);To explore the possible mechanism of Xixin Decoction in the treatment of Alzheimer disease(AD).Methods Totally 60 SAMP8 mice were randomly divided into model group,probiotics group,and Xixin Decoction high-,medium-and low-dosage groups,with 12 mice in each group,another 12 SAMR1 mice were set as control group.The medicated groups received corresponding drugs by gavage for 10 weeks respectively,while the control group and model group were gavaged with equal volume of distilled water.Morris water maze test was used to detect the learning and memory ability of mice,the blood-brain barrier permeability was detected by Evans blue method,the contents of matrix metalloproteinase 9(MMP9),nuclear factor(NF)-κB and tumor necrosis factor-α(TNF-α)in serum were determined by ELISA,the expressions of P-gp,CB1 and CB2 in hippocampal tissue were detected by Western blot,P-gp expression in hippocampal tissue was detected by immunofluorescence staining.Results Compared with the control group,the learning and memory ability of mice in model group significantly decreased,Evans blue exudation in brain tissue significantly increased,the contents of MMP9,TNF-α and NF-κB in serum significantly increased,the expressions of P-gp and CB2 protein significantly decreased,the expression of CB1 protein significantly increased,with statistical significance(P<0.01,P<0.05).Compared with the model group,the learning and memory ability of mice in Xixin Decoction high-dosage group significantly increased,the Evans blue exudation in brain tissue significantly decreased,the contents of MMP9,TNF-α and NF-κB in serum significantly decreased,the protein expressions of P-gp and CB2 significantly increased,and the protein expression of CB1 significantly decreased,with statistical significance(P<0.01,P<0.05).Conclusion Xixin Decoction can improve the spatial learning and memory ability of AD model mice,and its mechanism is related to regulating the permeability of the blood-brain barrier and related protein expression,and inhibiting neuroinflammation.

ObjectiveTo observe the possible mechanism of Xixin Decoction （洗心汤， XXD） in the prevention and treatment of Alzheimer 's disease（AD）. MethodsFifty rapid aging model mice （SAMP8） were randomly divided into model group， probiotic group， high-， moderate- and low-dose group of XXD， with 10 mice in each group. Another 10 homologous anti-rapid aging mice （SAMR1） were set as control group. After 10 weeks of feeding， the control group and the model group were given 10 ml·kg^-1·d^-1 of distilled water by gavage， while the probiotic group （0.39 g·kg^-1·d^-1）， the high-dose group of XXD （5.08 g·kg^-1·d^-1）， the moderate-dose group of XXD （2.54 g·kg^-1·d^-1）， and the low-dose group of XXD （1.27 g·kg^-1·d^-1） were given corresponding drugs or decoctions by gavage， once a day in all groups. After 10 weeks of intragastric administration， Morris water maze was used to detect the spatial learning and memory ability of mice in each group. HE staining was used to observe the pathological changes of hippocampal CA3 region and colon. The levels of β-amyloid 1-42 （Aβ_1-42）， lipopolysaccharide （LPS）， serum amyloid A （SAA） and acetylcholine （ACH） in hippocampus and colon were detected by ELISA.The diversity of intestinal flora in mouse feces was detected by 16S rRNA sequencing. ResultsCompared to those in the control group， the levels of Aβ_1-42，LPS， SAA increased， while the level of ACH decreased in the model group （P＜0.05 or P＜0.01）. Compared to those in the model group， the escape latency period of the probiotic group was significantly shortened on the 2nd and 5th days， while the escape latency period was shortened， and the residence time in the target platform quadrant increased in the high-dose XXD group during the 2nd to 5th days； the escape latency period was shortened significantly in the moderate-dose XXD group on the 5th day （P＜0.05 or P＜0.01）. Compared to those in the model group， the hippocampal neuron cells in the high- and moderate-dose XXD groups were arranged more closely， with decreased levels of SAA， Aβ_1-42 and LPS， increased ACH level， Simpson and Shannon index （P＜0.05 or P＜0.01）； the arrangement of hippocampal neuron cells in the probiotic group and the low-dose XXD group was relatively loose； the proportions of Bacteroidetes and Prevotella were significantly reduced in the probiotic group and the high-dose XXD group， while that of Firmicutes and Lactobacillus significantly increased （P＜0.05 or P＜0.01）. Compared to those in the probiotic group and the high-dose XXD group， the number of goblet cells in the moderate-dose XXD group decreased， and the number of glands in the low-dose XXD group decreased with atrophy. The high-dose XXD group had decreased Aβ_1-42 level in the hippocampus， increased ACH level in thehippocampus and colon tissue， and decreased SAA in the colon tissue than the moderate- and low-dose XXD groups （P＜0.05 or P＜0.01）； moreover， the SAA level in the hippocampus was significantly higher in the low-dose XXD group than the high- and moderate-dose groups （P＜0.01）. ConclusionXXD can improve the spatial learning and memory ability of SAMP8， reduce the production and deposition of LPS， SAA and Aβ_1-42 in brain and intestine， and increase the content of ACH. The mechanism of its prevention and treatment of AD maybe related to regulating intestinal microecology， affecting flora diversity and improving inflammatory response.