Study On Neuroinflammation In Parkinson Disease

Background The mechanisms of Parkinson disease (PD) is still not fullly clear.Blood-brain barrier dysfunction has been reported in PD.The pathogenesis of PD may at least be linked to blood-brain barrier dysfunction.Tight junction proteins including ZO-1 and occludin can be degraded by metallomatrixprotease 9 (MMP9).Pharmacological inhibition of MMP expression protected against loss of dopaminergic neurons directly. Erythropoietin have neurovascular protection in many CNS disease through decreasing BBB disruption.Objective To investigate the expression of ZO-1,occludin and the activity of MMPs (MMP9 and MMP2) in ventral midbrain and caudate putamen of subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) Parkinson mouse model.This study was designed to explore the possible beneficial effects of systemically given EPO on tight junction proteins (ZO-1 and occludin) and the activity of MMPs (MMP9 and MMP2) in MPTP-treated PD model.Methods Male C57BL/6 mice were divided into four groups.Group 1 control mice were treated for one week with vehicle [phosphate-buffered saline (PBS)]. Group 2 control mice received human recombinant erythropoietin (5,000 IU/kg/day, i.p.) for one week. Group 3 mice received MPTP (20 mg/kg/day) for one week.Group 4 mice received erythropoietin (5,000 IU/kg/day, i.p.)and MPTP (20 mg/kg/day, i.p.) for 7 consecutive days.Erythropoietin was injected 30 min prior to MPTP administration.Animals were sacrificed one day after the last injection.Gelatinolytic (MMP-2 and MMP-9) activity in the striatum and ventral midbrain was measured by zymography. Immunoblot analysis was used to confirm the levels of tight junction proteins (occludin and ZO-1).The expressionof ZO-1 and dopaminergic neuron loss of subacute mice model was observed by using TH and ZO-1 staining.Results The activity of MMP-9 and MMP-2 is upregulated in the ventral midbrain and striatum of subacute MPTP parkinson mice model,and the effect is blocked by erythropoietin.MPTP decreased tight junction (ZO-1 and occludin) in the ventral midbrain and striatum,and the effect was attenuated by erythropoietin.The number of TH positive cells was decreased after MPTP treatment, and the dopaminergic neuron loss was attenuated by erythropoietin.The expression of ZO-1 in the ventral midbrain and striatum is decreased after MPTP administration,and this effect was attenuated by erythropoietin.Conclusion Erythropoietin may attenuate tight junction proteins decrease in ventral midbrain and striatum of subacute MPTP Parkinson model mediated by blocking the activity of MMP9 and MMP2.The neuroprotective effect of EPO might be mediated by reduced activation of MMP-9,MMP2,and the disruption of the blood-brain barrier.Background CD4+ and CD8+ T cells were observed in the SNPC,Infiltration of CD4+ lymphocytes into the brain contributes to neuronal cell death in a mouse model of Parkinson disease.Conventional models of lymphocyte transmigration indicate a requirement for both ICAM-1/LFA-1 and VCAM-1/VLA-4 interactions,so adhesion molecules may be very important in the process.Objective To explore the mechanism of T cell extravasation,we surveyed the expression of VCAM-1 and ICAM-1 in ventral midbrain of acute 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP) Parkinson mouse model,and CD49d was also detected in the patients of Parkinson disease.Methods C57BL/6 mice of acute MPTP Parkinson model group received 4 intraperitoneal injections of MPTP (20 mg/kg) at 2-h intervals and were sacrificed one day and one week after the last injection.CD8+ T cell of acute MPTP mice model was observed by immunohistochemistry.The expression of VCAM-1 and ICAM-1 in these samples were analyzed by Quantitative RT-PCR or Western blot analysis.VLA-4(CD49d) were examined in peripheral CD4+ lymphocytes of Parkinson patients and normal control by flow cytometry.Results CD8+ lymphocytes was observed in the ventral midbrain of acute MPTP mice model.The expression of ICAM-1 but not VCAM-1 was increased in the ventral midbrain of mice treated with MPTP (acute Parkinson models) in comparison to untreated animals.Compared with control,CD49d was not upregulated in Parkinson patients.Conclusion Upregulation of ICAM-1 suggests it may play important role in infiltration of CD4+ lymphocytes into the brain.ICAM-1 may facilitate immune cell migration into areas of degeneration. Anti-IC AM-1 antibody may attenuate migration of lymphocytes,and reduce neuron damage.Objective To investigate the expression of CD14,TLR2,and TLR4 mRNA in ventral midbrain and caudate putamen of acute and subacute 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP) Parkinson mouse model.Methods Male C57BL/6 mice were divided into four groups which were:PBS control group(8-10-week-old),8-month-old (middle-aged) group, subacute and acute Parkinson mice model group. Model mice were intraperitoneally injected with MPTP (20 mg/kg) once daily for consecutive 7 days or received 4 intraperitoneal injections of MPTP (20 mg/kg) at 2-h intervals and were sacrificed one day after the last injection. Control mice (8-10-week-old group and middle-aged group) received saline solution only. Dopaminergic neuron loss of subacute mice model was observed by using TH staining. Astrocyte of subacute mice model was observed by by using GFAP stain.The expression of CD 14 mRNA,TLR2 mRNA and TLR4 mRNA in these samples were analyzed by RT-PCR.Results The number of TH positive cells in the ventral midbrain was decreased,and the number of GFAP positive cells increased in the ventral midbrain and striatum after MPTP treatment.The expression of CD 14 mRNA but not TLR2 mRNA and TLR4 mRNA was increased in the ventral midbrain and striatum of mice treated with MPTP (both acute and subacute Parkinson models) in comparison to untreated animals.Conclusion The overexpression of CD14 mRNA suggests it may be possible involvement of non-specific neuroinflammatory phase response in the pathophysiology of Parkinson.The expression of CD 14 and TLR2/4 may be involved in spatio-temporal distribution of inflammatory reaction following MPTP treatment.