3-hydroxy Methyl Butyrate On Two Kinds Of Dementia Mice Model Of Learning Ability Of Space Effect And Its Molecular Mechanism

Alzheimer’s disease is also known as senile dementia with high incidence in people over the age of 50. It is a neurodegenerative disease caused by environmental, genetic and other factors and mainly characterized by cognitive impairments. Its pathological manife-stations include neuron apoptosis and reduction in the prefrontal cortex and hippocampal area, neurofibrillary tangles, elderly spots, etc. A variety of hypotheses has been put for-ward on the pathogenesis of Alzheimer’s disease, including theories on genes, AP toxicity, abnormal modification of Tau protein, free radical damage, the disequilibrium of calcium homeostasis, apoptosis, metabolic disorders, and cholinergic theory, etc.3-hydroxy butyrate (3-hydroxybutyric acid) is one of the main composition of ke-tone bodies produced after human lipid mobilization. The brain cannot store glycogen as energy storage, but in the case of glycogen scarcity, the brain cells will start the abnormal lipid mobilization and protein consumption as energy compensation resulting in brain metabolism disorders, abnormal cell death, leading to cognitive impairments and other symptoms. Ketone bodies can be used as the semi-finished energy product directly by the brain. Being an uncharged neutral small molecule,3-hydroxybutyrate is easy to penetrate the blood brain barrier and thus timely compensate brain power.3-hydroxy butyric acid methyl ester (3-hydroxy butyricacid methyl ester, HBME) is the methyl ester substance of 3-hydroxy butyric acid. Like 3-hydroxybutyric acid, HBME has good blood brain barrier permeability. Previous studies have shown that, in normal mice,3-hydroxybutyric acid and its methyl ester can enhance metabolic efficiency, reduce free radical damage, promote cell growth, protect nerve cells and has a certain improvement in learning mem-ory ability and a variety of functions.In this thesis, the transgenic mice (APPswe) with amyloid precursor protein (APP) single gene overexpression were used as the dementia model because its characteristic pathological dementia is caused only by the A beta accumulation. Senescence accelerated mice (SAMP8) were also used as the age-related dementia model for characterization of cognitive impairment and its close relative homology senescence resistant mice (SAMR1) were used as the negative control. The impact of HBME on learning cognitive ability and the possible mechanism were studied in these two models.The main results include:(1) through the experiment of acute toxicity, accumulative toxicity test in normal mice, subacute toxicity test,Ames test and in vitro mammalian cell micronucleus test for toxicological safety evaluation of three hydroxymethyl butyrate. The experimental results show that:3-hydroxybutyrateno acute toxicity, cumulative toxicity,mutagenicity and toxicity of chromosomal damage, according to the relevant exogenous chemi-cals toxicological safety evaluation of evaluation index system for the safe, non-toxic substances.(2) to APP over expression of single transgenic mice and senescence accelerated mouse for two kinds of dementia model mice, are respectively arranged in blank con-trol group and experimental group, blank groupwere given saline, the experimental group were administered intragastrically with different concentrations (20,40,60 mg/kg/d) 3-hydroxy butyric acid methyl ester. After 10 weeks, the behavioral experi-ments using the Morris water maze. The experimental results show that,3-hy-droxy methyl butyrate obviously improve the learning and memory ability, two kinds of dementia model mice, at the same time for two kinds of senile dementia model mice in long term memory also showed remarkable promotion effect, improve the effect showed a dose dependent relationship, in high concentration dose group to enhance the effect of the most significant.(3) The above two kinds of dementia model mice at the end of the Morris water maze behavior after the experiment, the rats were sacrificed and the brain, by pro-tein immunization technique (Western Blot Assay),carries on the related protein in learn-ing and memory related and superior frontal epithelial tis sue:CREB(cAMP-response element binding protein, CREB) and phosphorylated CREB, thioredoxin (thioredoxin, Trx),cyclindependent kinase-5 (cyclin-dependent kinase-5, Cdk5), B lymphocyte tumor-2 gene (B-cell lym-phoma-2, Bcl-2) of caspase-3 pre-cursor (pro-caspase-3) and caspase-3 precursor-9 (pro-caspase-9) the detection and anal-ysis. The results show, different concentrations of 3-hydroxy methyl buty- rate were up-regulated expression of two kinds of dementia model mice in hippocam-pus and frontal cortex tissue CREB andphosphorylation of CREB, Trx, Cdk5 and Bcl-2 protein expression of pro-caspase-9, pro-caspase-3, two kinds of dementia model mice hippocampus and frontal cortex tissue without falling. The experimental results show that,3-hydroxy methyl butyrateon two kinds of dementia model of learning and memory ability and improve itsmechanism may be through the signal transduction path-way of CREB/Cdk5; by using Trx to reduce free radical damage; and through Bcl-2 expression upregulation stabilize an inactive precursor apoptosis factor Caspase-3 and Caspase-9, to prevent the cutting, inhibit nerve cell apoptosis pathway; structure and function to protect and repair neurons, so as to promote and improve two kind of dementia model of learning and memory of mice.Improve the role in two brain re-gions of two kinds of dementia model mice showed 3-hydroxybutyrate dose depen-dent, in the effect of high concentration group was obviously, indicated that 3-hydroxy methyl butyrateenhanced metabolic efficiency promoting the growth of cells, protect nerve cells.In summary,3-hydroxy methyl butyrate is safe and non-toxic, significant improve-ment on learning and memory ability of two kinds of dementia model mice, its mechanism may be through the strengthening of improvedmetabolic efficien-cy promoting the growth of cells, protect nerve cells, regulation of learning and memory signal transduction pathway, initiated free radical scavenging and inhibiting neuronal apoptosis pathway.This thesis provided the basic theory research with 3-hydroxybutyric acid methyl ester as a possible anti senile dementia and delay the developmentof aging medicine.