Based On The MyD88/NF-?B Pathway To Explore The Mechanism Of Warming The Spleen And Raising The Yang Method To Prevent And Treat Cognitive Impairment In Rats

Purpose:Based on the previous research results and the research status of modern medical pathology mechanism of AD,this study established the rat model of cognitive impairment of spleen yang deficiency,explored the relationship between inflammation and peroxidation damage in the state of spleen deficiency and AD,and regulated the inflammation and oxidative stress indicators of cognitive impairment rats of spleen yang deficiency with the method of warming spleen and lifting yang,evaluated the therapeutic mechanism of warming spleen and lifting yang method in the prevention and treatment of AD from the perspectives of behavior,pathology and proteomics,and to provide theoretical and experimental basis for the prevention and treatment of AD in traditional Chinese medicine.Material and method:In this experiment,SPF healthy SD rats aged 3 months were used,30 male and 30 female.The rats were randomly divided into four groups: normal group,cognitive impairment with spleen yang deficiency model group,positive drug control group(referred to as western medicine group)and Wenpi Shengyang Yizhi formula group(referred to as Chinese medicine group).The model of spleen yang deficiency syndrome was established in two stages with compound factors: the first 8 days were treated with improper diet and excessive fatigue,and the last 8 days were treated with yang injuring drugs to establish the model of spleen yang deficiency syndrome.The model of cognitive impairment was established by injecting A?1-42 oligomer into CA1 region of hippocampus and then evaluated.The next stage lasted for 4 weeks,and adrug intervention method was used: Wenpi Shengyang Yizhi Decoction and Aricept were given respectively,At the fourth week of treatment,water maze adaptive training,positioning navigation and space exploration experiments were carried out in order to evaluate the learning and memory ability of rats in different groups.Then the brain tissue,hippocampus and blood were taken.The expression of serum TNF-??IL-6?MDA and SOD were detected by ELISA.The morphological changes of neurons in brain tissue were observed and analyzed by HE staining.The protein expressions and mRNA of TLR₄?MyD88?NF-?B in brain tissue were detected by RT-PCR and WB method.Results:1 General state of rats results: At the end of the spleen yang deficiency syndrome model stage,compared with the normal group,the weight,Anal temperature and swimming endurance of rats in the model group(including the model group,the western medicine group and the traditional Chinese medicine group,the same below)were significantly decreased(P<0.01),accompanied by bow back,squint,mental depression,fatigue,loose stool and other symptoms.2 Behavioral detection results of rats2.1 Positioning navigation experiment: compared with the normal group,the decrease of escape latency in the model group was reduced(P<0.01),and compared with the model group,the decrease of escape latency in the western medicine and the traditional Chinese medicine groups were increased(P<0.01).2.2 The space exploration experiment: compared with the normal group,the proportion of activity time of target quadrant in the model group was significantly shorter,the number of crossing the platform were significantly reduced(P<0.01),and the spending time of the first time to reach the platform was longer(P<0.01).Compared with the model group,the proportion of activity time of target quadrant in the western medicine and the traditional Chinese medicine groups were significantly longer,the number of crossing the platform was significantly increased(P<0.01),and the spending time of the first time to reach the platform was significantly reduced(P<0.01).3 Morphological results: after HE staining,the neurons in the hippocampus of the normal group were evenly stained,arranged in order,with a large number,round like nuclei and clear nucleoli.In the model group,the number of pyramidal cells decreased,arranged irregularly,the nucleolus pyknosis and the nucleus was deeply stained.Compared with the model group,the number of hippocampal neurons in the western medicine and Chinese medicine groups were significantly increased,but still lower than that in the normal group,the nuclear staining was relatively clear and orderly,and the amount of cell pyknosis and necrosis was reduced.4 ELISA results: compared with the normal group,the expression levels of TNF-?,IL-6 and MDA in the model group increased significantly(P<0.01),and the activity of SOD decreased(P<0.01);compared with the model group,the expression levels of TNF-?,IL-6 and MDA in the western medicine and traditional Chinese medicine groups decreased significantly(P<0.01),and the activity of SOD increased significantly(P<0.01).5 Western blot results: compared with the normal group,the protein expression levels of TLR₄,MyD88 and NF-?B in model group increased significantly(P<0.01),and the protein expression levels of TLR₄,MyD88 and NF-?B in the western medicine and traditional Chinese medicine groups were decreased significantly(P<0.01).6 RT-PCR results: compared with the normal group,the mRNA expression levels of TLR₄,MyD88 were significantly increased(P<0.01),and the mRNA expression levels of NF-?B were significantly increased(P<0.05)in the model group;compared with the model group,the mRNA expression levels of TLR₄ and MyD88 decreased significantly(P<0.01),and the mRNA expression levels of NF-?B decreased significantly(P<0.05)in the western medicine and traditional Chinese medicine groups.Conclusions:1 Spleen yang deficiency can activate the inflammatory response and oxidative stress damage in the brain,and promote the release of a large number of inflammatory factors by microglia and astrocytes to produce neurotoxicity,which may cause the damage of neuron function and cognitive impairment.2 The therapeutic method of warming spleen,lifting yang and promoting intelligence can reduce the level of inflammatory factors and lipid peroxidation products in brain tissue of rats with cognitive impairment of spleen yang deficiency,and improve the activity of antioxidant enzymes and delay the disease.