The Improvement Effect Of Astrocyte FEZ-1 On Cognitive Function In PD Rat Model

Parkinson's disease(PD)is a neurodegenerative disease.The main pathological features are progressive degeneration and death of dopaminergic neurons in the midbrain substantia nigra,which often accompanied by complications such as cognitive dysfunction.Fasciculation and elongation protein zeta-1(FEZ-1),is involved in neurodevelopment and axonal extension and bundle formation in mammals.It is expressed in both neurons and astrocytes in the brain,and astrocytes FEZ-1 have nerve repair effects.Recent studies have suggested that FEZ-1 has synaptic plasticity and is related to learning and memory.Lithium chloride(LiCl)is a glycogen synthase kinase-3?(GSK-3?)inhibitor,which can effect astrocytes to promote the expression of FEZ-1,and has an improving effect on neurodegenerative diseases.This study investigated FEZ-1 expression in PD animals with cognitive impairment and increased astrocyte FEZ-1 expression through intraperitoneal administration of lithium chloride to observe the role and mechanism of astrocyte FEZ-1 in PD animal cognitive impairment improvement.Objective:Explore the role and mechanism of astrocyte FEZ-1 in PD rat with cognitive impairmentMethods:(1)Stereotactic injection of 6-OHDA into the medial forebrain bundle to establish a PD rat model.The Y-maze and open field test were used to evaluate the cognitive ability of PD rats,according to the cognitive ability grouping for the sham group,non-cognitive impairment group and PD cognitive impairment group.Western blot was used to detect the expression levels of GFAP,FEZ-1,TH,and p-GSK-3? in nigrostriatal tissue.Immunofluorescence histochemical technique was used to observe the TH expression in the substantia nigra of PD model and the expression of astrocyte FEZ-1 in the substantia nigra striatum of each group.Intraperitoneal administration of lithium chloride(80 mg/kg)in PD cognitive impairment model.Open field test,Y maze evaluate the improvement of cognitive ability.Western blot detect the expression of GFAP,TH,FEZ-1,and p-GSK-3? in nigrostriatal striatum of three group.Immunofluorescence histochemical techniques was used to observe astrocyte FEZ-1 expression changeResults:(1)Two weeks after 6-OHDA injection,PD rats exhibited typical rotation behavior.TH immunofluorescence staining showed that the number of neurons was significantly reduced in the dense substantia nigra of PD.(2)Y-Maze experiment showed that most(83.3%)of the PD rat models with cognitive impairment.Open-field test showed that the number of crossing and rearing of PD model group decreased,time staying in center was significantly longer.(3)Western blot results showed that FEZ-1 expression levels was reduced in the substantia nigra and striatum of the PD cognitive impairment group,while the expressions of TH and p-GSK-3? were also decreased,In addition,GFAP expression was increased in both non-cognitive impairment group and PD cognitive impairment group.(4)Immunofluorescence histochemistry revealed that the expression level of FEZ-1 decreased in the striatum and substantia nigra of the PD cognitive impairment group,compared with the sham group,while the expression of FEZ-1 in astrocytes increased.(5)Co-immunoprecipitation(CO-IP)results show that FEZ-1 interacts with GSK-3?,suggesting that astrocyte FEZ-1 may function through interaction with GSK-3?.(6)Intraperitoneal administration of lithium chloride(80 mg/kg)to the PD cognitive impairment model.The open field experiment and Y-Maze experiment showed that compared with the PD cognitive impairment group,the cognitive ability of the administration group was improved.(7)Western blot results showed that compared with PD cognitive impairment group,FEZ-1 expression was significantly increased in substantia nigra and striatum of the administration group,TH,p-GSK-3? expression was up-regulated,and GFAP expression was no change.(8)Immunofluorescence histochemical experiments found that compared with PD cognitive impairment group,the expression of total FEZ-1 and FEZ-1 in astrocytes in the administration group were increased.Conclusions:(1)Behavioral test show that most of PD model rats have cognitive impairment.(2)The expression of FEZ-1 protein decreased in PD rats with cognitive impairment,suggesting that FEZ-1 may play an important role in the cognitive function of Parkinson's disease.The interaction between FEZ-1 and GSK-3? and the synchronous expression of FEZ-1 and p-GSK-3? proteins in the PD cognitive impairment group suggest that the role of FEZ-1 in regulating cognitive function is related to the active state of GSK-3?.(3)After the administration of lithium chloride,the expression of FEZ-1 and p-GSK-3? were up-regulated in astrocytes of the substantia nigra and striatum of PD cognitive impairment rats,the learning and memory ability is obviously improved.It is suggested that lithium chloride can improve the cognitive function of PD model rats.The mechanism may be to regulate the activity of GSK-3? to promote the expression of FEZ-1 in astrocytes,which can alleviate and improve the cognitive impairment of PD.