The Blockage Of T Lymphocytes Migration Into The Brain In Alzheimer's Disease By CXCR₂ Receptor Antagonists

PurposeAlzheimer's disease(AD) are age-related chronic degenerative diseases of nervous system,seriously affecting the quality of life of older persons.Therefore,studying the pathogenesis of AD,to explore prevention and treatment targets for AD intervention is focused on neuroscience.AD animal models are an important tool for research work. At AD risk factors on the course of the study,we found that amyloidβ-protein(Aβ) deposition in the brain are the early event in AD,and a key link in the process. Aggregation of Aβexert neurotoxicity,activated the AD pathology process,including a wide range of glial cell activation,inflammatory micro-environment,neuronal dysfunction and death.Aβdeposition in brain activation with the phagocytic activity of microglial,caused by congenital immune response(innate immune response).Aβcan raise the peripheral blood immune cells through the blood-brain barrier into the brain to the inflammation site of aggregation,caused by adoptive immune responses(adaptive immune response) is unclear.Blood-brain barrier composed by the microvascular endothelial cells,basement membrane and astrocytes foot,will be separated from brain parenchyma and blood.Under normal circumstances,the immune system cells and molecules can not freely enter the brain.However,with the continuous progress of research,we gradually realize that,even in the physiological status,the central nervous system also exist within the process of immune surveillance.Peripheral lymphocyte can take the initiative into the brain parenchyma,the brain's immune response to start to remove the factor may lead to the brain lesions.Lymphocytes across the blood-brain barrier is a complex process.Lymphocytes and microvascular endothelial cells play an important role,which surface expression of intracellular adhesion molecule and its receptor interaction.Chen Yu-hua Research Group in the study of T cells through the blood-brain barrier mechanism in the process of AD patients found that peripheral T lymphocytes through the blood-brain barrier in vitro model-the human brain microvascular endothelial cell monolayer significantly increased the ability of cross the cell monolayer,and confirmed that T lymphocytes in peripheral blood of AD patients with high expression of CXCR2 receptor;CXCR2 receptor cells are an important factor receptor family 1,reactive with its ligand IL-8 to chemotatic lymphocytes migration in vitro and in vivo.Based on,this study used rat brain stereotactic injection method,the establishment or Aβdeposition in the brain of the animal model,while intraperitoneal injection CXCR2 receptor antagonist to block the T lymphocyte migration into the brain,to examine the role of T lymphocytes at AD lesions,while analysis of the possible mechanisms of T lymphocytes into the brain.Methods1,Experiments in vivo(1),Rat brain stereotactic injection technology will injected aggregate Aβ_1-42 into bilateral hippocampus of rats,intraperitoneal injection of CXCR2 receptor antagonist SB-332235-Z or blockers solvent peg-400,the control group injection equal volume of Aβ42-1.(2),Immunohistochemical staining method was used to observe the microglial cells expressed CD11b,MHC-Ⅱchange,while blocking T lymphocytes into the brain.(3),Immunofluorescence detect the expression of neuronal caspase-3 activation fragment changes,while block T lymphocytes into the brain. (4),The application of immunofluorescence used to detect in cerebral microvascular endothelial expression of MHC-Ⅰchange.2,Experiments in vitro.(1),Western-blot investigate the effect of Aβ_1-42 on HBMECs at different time points on MHC-Ⅰ/Ⅱprotein expression changes.(2),The culture supernatant of BV2 sitimulates HBMECs detection of proteins by Western-blot at different time points MHC-Ⅰ/Ⅱprotein expression changes.(3),Aβ1-42-stimulated culture supernatant of BV2 co-culture with HBMECs detection of proteins by Western-blot at different time points MHC-Ⅰ/Ⅱprotein expression changes.(4),Flow cytometry detection of MHC-Ⅰmolecules expression changes,which Aβ_1-42 sitimulate HBMECs at different point.Results1,Successfully prepared Aβdeposition in the brain of the AD model.2,Compare with Aβ_42-1,rats with bilateral hippocampal injection of Aβ_1-42 aggregation increasely activate microglial cells.Aβdeposition caused CDllb-positive microglial cells significant increase in the number and activated.3,T lymphocytes enhanced Aβdeposition caused activation of microglial cells.Rats with bilateral hippocampal injection of Aβ1-42 aggregation,compare with peg-400,intraperitoneal injection of SB-332235-Z significant reduction in quantity of CDllb-positive microglial cells.4,Block T lymphocytes into the brain can reduce neuronal apoptosis.Rats with bilateral hippocampal injection of Aβ-42 aggregation after intraperitoneal injection of SB-332235-Z,compare with the intraperitoneal injection of peg-400 control group,inhibition of neuronal apoptosis in hippocampus.5,AD model rat brain microvascular endothelial cell high expression of MHC-I molecules may be involved in T lymphocyte antigen-presenting brain to process.ConclusionBlocking T lymphocytes into the brain reduced Aβdeposition caused by the activation of microglia and inhibit neuronal apoptosis,brain microvascular endothelial cells involved in T lymphocyte antigen-presenting process into the brain to be further explored.