Study On The Effect And Mechanism Of Shaoyao Gancao Decoction On P38MAPK Signaling Pathway In AD Model Rats Based On Inflammatory Reaction

Objective:Based on the previous research results and literature reports on Alzheimer’s disease,this paper explores the improvement effect of Shaoyao Gancao Decoction on AD model rats.Combining with the results of behavior and pathology,the mechanism of Shaoyao Gancao Decoction on AD model rats is comprehensively analyzed from the point of inflammatory reaction.Method:Theoretic discussion: Refer to the Chinese and English literatures related to Alzheimer’s disease,analyze the pathogenesis and research status of AD from traditional Chinese medicine,modern Chinese medicine and international frontier,at the same time refer to the pharmacodynamic material basis and pharmacological effects related to Paeonia lactiflora,Licorice and Shaoyao Gancao Decoction,in order to provide theoretical basis for exploring the effect and mechanism of Shaoyao Gancao Decoction on AD model rats.Experimental study: Forty-five SPF SD rats were used in the experiment.AD model was duplicated by injecting Abeta 1-42 into hippocampal CA1 region.After successful modeling,the rats were administered continuously for 30 days.Water maze behavioral tests were performed after gastric administration.Immediately after the end of the behavioral experiment,the whole brain and hippocampus of rats were taken for Nissl staining,ELISA,RT-PCR,immunohistochemistry and WB detection,respectively.Specific detection indicators are as follows:1 Effects of Shaoyao Gancao Decoction on Learning and Memory Ability of AD Model RatsMorris water maze experiment was used to observe the effect of Shaoyao Gancao Decoction on positioning navigation and space exploration ability of AD model rats.2 Effects of Shaoyao Gancao Decoction on hippocampal pathology in AD ratsThe morphology and number of neurons in hippocampal CA1,CA3 and DG regions were observed by Nissl staining.3 Effect of Shaoyao Gancao Decoction on the expression of A beta in AD model ratsThe expression of Abeta 1-40 and Abeta 1-42 in hippocampus was detected by ELISA.4 Effect of Shaoyao Gancao Decoction on Inflammatory Response in AD Model RatsThe morphology and quantity of positive microglia in hippocampal CA1,CA3,DG and CORT regions were detected by immunohistochemistry,the expression of IL-1beta and COX-2 in hippocampal tissue of rats were detected by RT-PCR,and the expression of IL-6 and TNF-alpha in hippocampal tissue of rats was detected by ELISA.5 Effect of Shaoyao Gancao Decoction on p38 MAPK Signaling Pathway in AD Model RatsThe expressions of p38,p-p38 and p65 in hippocampus of AD rats were detected by WB method.Results:1 Effects of Shaoyao Gancao Decoction on Learning and Memory Ability of AD Model Rats1.1 Positioning Navigation ExperimentsCompared with the blank control group,there was no significant change in the time to go up the platform and the total distance to swim in the sham-operated group(P>0.05).The time to go up the platform and the total distance to swim in the model group increased significantly(P<0.01).Compared with the model group,the time to go up the platform and the total distance to swim in the western medicine group and Shaoyao Gancao Tang group decreased in varying degrees,and the difference was significant(P<0.01).The difference was significant(P<0.01).Compared with the western medicine group,there was no significant change in the plateau time(P>0.05)and total swimming distance(P<0.05)in the Shaoyao Gancao Decoction group.1.2 Experiments of Space ExplorationCompared with the blank group,there was no significant change in the number of rats crossing the original platform in sham-operated group(P>0.05),and the number of rats crossing the original platform in model group decreased significantly(P<0.01);compared with model group,the number of rats crossing the original platform in western medicine group and Shaoyao Gancao Decoction group increased significantly(P<0.01);compared with western medicine group,the number of rats crossing the original platform in sham-operated group increased significantly(P<0.01).The number of rats crossing the original platform decreased in Shaoyao Gancao Decoction group,but there was no significant difference(P>0.05).Compared with the blank group,the time of rats in the target quadrant in the sham-operated group increased slightly,but there was no significant difference between the two groups(P>0.05),while the time of rats in the third quadrant in the model group decreased significantly(P<0.01).Compared with the model group,the time of rats in the target quadrant in the western medicine group and Shaoyao Gancao Tang group increased significantly.Compared with the western medicine group,the time spent in the target quadrant of rats in Shaoyao Gancao Decoction group decreased slightly,but the difference was not significant(P>0.05).2 Effects of Shaoyao Gancao Decoction on hippocampal pathology in AD ratsNissl staining results The neurons in CA1,CA3 and DG regions of hippocampus in blank group and sham-operated group were normal in shape,neat in arrangement and complete in structure.The nuclei were mostly spherical or elliptic,and there were clear Nissl bodies in the cytoplasm.The morphology of neurons in CA1,CA3 and DG regions of hippocampus in model group changed greatly,which showed that neurons were mostly lost and arranged sparsely,and neurons were atrophied and deformed,while the number of Nissl bodies in cytoplasm decreased.After treatment with Shaoyao Gancao Decoction and Western medicine,the morphology and quantity of neurons in different areas of hippocampus were improved to varying degrees.3 Effects of Shaoyao Gancao Decoction on the expression of A beta in AD model ratsELISA results Compared with the blank group,the contents of Abeta 1-40 and Abeta 1-42 in the hippocampus of rats in sham-operated group had no significant change(P>0.05),while the contents of Abeta 1-40 and Abeta 1-42 in the hippocampus of rats in model group increased significantly(P<0.01);compared with model group,the contents of Abeta 1-40 and Abeta 1-42 in the hippocampus of rats in western medicine group and Shaoyao Gancao Decoction group decreased significantly,and the differences were extremely significant(P<0.01);Compared with western medicine group,the content of Abeta 1-40 in hippocampus tissue of rats in Shaoyao Gancao Decoction group increased,but the difference was not significant(P>0.05),and the content of Abeta 1-42 increased with significant difference(P<0.01).4 Effect of Shaoyao Gancao Decoction on Inflammatory Response in AD Model Rats4.1 Immunohistochemical results Compared with the blank group,the morphology and quantity of positive microglia in the hippocampus of rats in sham-operated group did not change significantly.The body staining of positive microglia in the hippocampus of rats in model group was deepened,and the morphology was obviously increased.The damage of microglia in the hippocampus of rats in western medicine group and traditional Chinese medicine group was improved to varying degrees after administration.4.2 RT-PCR results Compared with the blank group,the expression of IL-1beta and COX-2 in hippocampus of rats in sham-operated group had no significant change,while the expression of IL-1beta and COX-2 in hippocampus of rats in model group was up-regulated;compared with model group,the expression of IL-1beta and COX-2 in hippocampus of rats in western medicine group and Shaoyao Gancao Decoction group was down-regulated;compared with western medicine group,the expression of IL-1beta and COX-2 in hippocampus of rats in Shaoyao Gancao deco-2.down-regulated expression of RNA.4.3 ELISA results Compared with the blank group,the expression of IL-6 and TNF-alpha in hippocampus of rats in sham-operated group had no significant change(P>0.05).The content of IL-6 and TNF-alpha in hippocampus of rats in model group increased more,and the difference between the two groups was very significant(P<0.01).Compared with model group,the content of IL-6 and TNF-alpha in hippocampus of rats in western medicine group and Shaoyao Gancao Decoction group decreased in different degrees.Compared with western medicine group,the contents of IL-6 and TNF-alpha in hippocampus of rats in Shaoyao Gancao Decoction group decreased,and the difference between the two groups was significant(P <0.01).5 Effects of Shaoyao Gancao Decoction on p38 MAPK Signaling Pathway in AD Model RatsWB experimental results Compared with the blank group,the expression of p-p38/p38 and p65 in the hippocampus of rats in sham-operated group did not change significantly(P>0.05),while the expression of p-p38/p38 and p65 in the hippocampus of rats in model group increased significantly(P<0.01);compared with model group,the expression of p-p38/p38 and p65 in the hippocampus of rats in each group decreased in varying degrees(P<0.01);compared with western medicine group,the expression of p-p38/p38 and p65 in the hippocampus of The expression of p-p38/p38 in hippocampus of rats in Decoction group increased significantly(P<0.05),but the expression of p65 did not change significantly(P>0.05).Conclusion:Shaoyao Gancao Decoction has a protective effect on AD model rats.Its mechanism may be related to reducing neuronal damage,inhibiting the expression of Abeta and inflammatory factors,interfering with microglia activation and p38 MAPK signaling pathway expression.