The Impacts Of Chronic And Exacerbated Asthma On The Learning And Memory Ability And On The Brain Inflammatory Response In Mice

Asthma is a type I allergic diseases. The pathogenesis of asthma is quitecomplex, the international medical community generally believed that asthma is avariety of cells and their cellular components involved in chronic inflammatorydiseases, changes in airway structure, one of the mechanisms of asthma, areconsidered to be associated with the severity of asthma and continuous reduce of lungfunction. In addition, virus infection, obesity, bronchial other types of diseases mighttrigger asthma.Anti-inflammatory therapy, symptomatic treatment and immunotherapy areconsidered the basic treatments for bronchial asthma. Among them,anti-inflammatory therapy is major treatment. Glucocorticoids are the most effectivedrugs to control airway inflammation. As the preferred way, inhalation enables themicro blood vessels to constrict, decrease inflammation exudate, relieve thesymptoms of bronchospasm, and reduce airway hyperresponsiveness. Budesonide, anon-halogenated glucocorticoidg high binding with receptors, is only available foratomization therapy of hormone. In this study, we established chronic worsen asthmamodel to observe the effects of asthma and budesonide atomization inhalation onlearning and memory ability of immature mice and the brain inflammation in maturemice. And the involved mechanisms were explored. Part Ⅰ: The impacts of chronic and exacerbated asthma onlearning and memory ability in immature miceObjection:Bronchus asthma, which is the most general and the highest frequency occurreddisease, is one of the most common chronic disease of respiratory system in currentsociety. About1in10children get the disease in the world and the number ofchildren which get the disease increases gradually. The researchers find that thereexits relationship between abnormal of brain function and a decrease in flow of brainblood in Harvard University. They argue that the chronic intermittent anoxia ofchildren has a disadvantage in growth, behavior and study. The result has alreadyreported in many researches. Therefore, it is said that asthma has an effect on thechildren capacity. When the children asthma starts to work, the oxygen reduces inquantity in the blood and the situation balances the supply of oxygen. Even thoughthe deprivation of oxygen in brain works in a short time, it has a bad effect on thegrowth of children brain. The aim of experiment is to build a model of chronic andexacerbation models of asthma and observe the situation of learning and memory andthe mechanism of action.Methods:1) Chronic exposure of sensitised mice to a mass concentration of10%aerosolised ovalbumin(ova) for10weeks.2)The determination of the ability oflearning and memory by Morris water maze.3) Examine bronchoalveolarlavage andhistopathology for deternmine the asthma model is successed.4) Thesuper-microstructure of observation of hippocampus of CA1region through biologicTransmission Electron Microscope(TEM).5) Using electrophysiogical recording toexplain the mechanisms of learning and memory in hippocampal CA1region.6)Using Real-time Polymerase Chain Reaction (PCR) to test the expression of mRNAin Glucocorticoid Receptors (GR), Brain-Derived Neurotrophic Factor (BDNF), Hypoxia-Inducible Factor1HIF1, Vascular Endothelial Growth Factor (VEGF),c-fos.7) Immunohistochemistry was performed to examine the number of possitivecells of ki67, Activity-regulated cytokeletal protein(Arc).8) Western blot to test theprotein level of c-fos, HIFI-、TEM5-1.Results:1) HE staining pathology detection and the counting results of inflammatory cellshow that chronic deterioration of asthma models have been successfully establishedand budesonide aerosol inhalation can improve airway inflammation;2) The watermaze behavioral experiments and the recording results in vitro brain sliceelectrophysiological show that chronic asthma can reduce the learning memory ofmice and budesonide therapy does not improve the barriers of learning and memory;3) Asthma induces lower synaptic density in hippocampus of mice and its structuraldefects; The mitochondrial density increases but there’s cristae inside;4) ThemRNA levels of Glucocorticoid Receptors(GR) and Brain-Derived NeurotrophicFactor(BDNF) in the brain of asthmatic mice reduces;5) The neural cellproliferation of asthmatic mouse was inhibited;6) The numbers of positive cells ofthe immediate early Activity-regulated cytokeletal protein(Arc) related to memoryand the expression of FBJ osteosarcoma oncogene(c-fos) are significantly lower thanthose of the control groups of asthmatic mice;7) the expression of related proteinVascular Endothelial Growth Factor(VEGF) and Tumor Endothelial cell Marker5(TEM5) has elevated, but the expression of Hypoxia-Inducible Factor1(HIF1-)has decreased;8) Budesonide aerosol inhalation has not effected the changes ofprotein expression mentioned above significantlyConclusion:1Chronic and exacerbated asthma damages hippocampal synapticultrastructure, down-regulates the learning and memory-related protein expression,impairs learning and memory ability in immature mice. 2Budisonid, as the important treatment of asthma, fails to ameliorate theability in learning and memory.Part Ⅱ: The impacts of chronic and exacerbated asthma onthe inflammatory response in the brain of miceObjection:Bronchia asthma contains a variety of cells and cell factors. The change ofsymptom is the inflammation of bronchia mucosa couple with edema of bronchiamucosa and airway remodeling which is induced by chronic inflammation motivationover a long time. The chronic inflammation of airway is the main cause that asthmaoccurs repeatedly and airway responses frequently. Controlling the chronicinflammation and restraining the airway remodeling have the important role on therecent researches. The aim of experiment is to build a model of chronic theaggravating asthma and observe the response situation of inflammation in the brain ofunderage rats of asthma when they stay in the environment which is lack of oxygenchronically over a long period.Method:1) Immunohistochemistry was performed to examine the number of possitivecells of GFAP, NeuN,ki67.2) Western blot to test the protein level of VEGF, TLR3,NF-κB3) The testing content of Tumor Necrosis Factor (TNF-, Interleukin-1(IL-1, Transforming Growth Factor type(TGF-, Interleukin-10(IL-10) in cortexand hippocampus through ELISA method. Results:1) pathologic detection and caculation of inflammatory cells expressed that wehad a successful preparation of the model for chronic and exacerbated asthma,meanwhile, Budesonide nebulization improved the airway inflammatory responseobviously;2) Activation of Astrocytes and microglia in the brain of ova group wereincreased while the bud group showed that the astrocytes were inhibited significantly;3)In the brain of the asthma mice, neurons had a increased death, the neuralregeration in DG was reduced. Bucdxonide nebulization can decrease the death of theneurons and promote the proliferation of neural cells.4) the expression of the VEGFwas increased in ova group which was inhibited obviously in bud group.5) Chronicasthma resulted in the increasing expression of the TLR3and the activation ofNF-κB, at the same time,it up-regulated the level of TNF-α and IL-1b; In bud group,the up-regulation of TNF-α and IL-1b were inhibited but the secretion of TGF-andIL-10were increased.Conclusion：1. Chronic asthma promotes the activation of glial cells in the brain of adultmice, increases the production of proinflammatory cytokines. These results indicatethat chronic asthma results in neuroinflammatory injury in the brain of mice.2. Budesonide inhalation can inhibit the activation of glial cells, reduce thesecretion of proinflammatory cytokines, increase secretion of anti-inflammatorycytokines, and thereby ameliorate the neuroinflammatory damage.3. Chronic asthma activates TLR3-NF-kB signal pathway to induceneuroinflammation in the mouse brain.. Budesonide inhalation inhibits theactivation of the above-mentioned signal pathway and plays its anti-inflammatoryeffects in the brain. Innovation:1. Chronic asthma leads to hippocampus ultrastructure damage in juvenile mice,suppresses to form LTP, and thereby damages the learning and memory ability ofjuvenile mice.2. Chronic asthma induces glial cell activation in adult mouse brain,upregulates and release of proinflammatory cytokines, increases exprssions ofinflammation-related proteins, and subsequently aggravates neuroinflammatoryinjury.3. Budesonide nebulization can significantly reduce cerebral inflammatoryinjury caused by asthma in adult mice; Budesonide nebulization fails to improve thedecline of learning and memory ability damaged by asthma in juvenile mice. Theseresults suggest that clinical therapies should be pay attention to the asthma-inducedbrain injury especially in children.