Neuroprotective Effect Of Chicoric Acid On 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Induced Zebrafish Models Of Parkinson’s Disease

Background: Chicory is a bitter vegetable,and chicoric acid(CA)is the main active ingredient of chicory,CA has been used in nutritional supplements,health foods and medicines due to its antioxidant,anti-inflammatory and anti-aging properties.Parkinson’s disease(PD)is a neurodegenerative disorder characterized by deterioration of motor function due to loss of dopaminergic(DA)neurons in the substantia nigra striatum(SNpc).Recent research has shown that food nutrients may have property and can be used to alleviate the symptoms of PD.Objective: To investigate the protective effect of Chicoric acid on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)induced zebrafish Parkinson’s disease model.Methods: Wild type AB-strain zebrafish larvae 24 hours post-fertilization(hpf)were randomly divided into control,MPTP model groups,and 1,5,25 n M CA groups.Everyday,after CA incubation 2 h,25 μM MPTP was added for modeling for 5consecutive days.The following parameters were evaluated at 7 days post-fertilization(dpf).The motor activity status of zebrafish was record by behavioral detection system to evaluate zebrafish movement function.2’,7’-Dichlorodihydrofluorescein diacetate(DCFH-DA)fluorescent was employed used to detect reactive oxygen species(ROS)to evaluate the oxidative stress damage degree of zebrafish.The levels of malondialdehyde(MDA)were assayed by microenzyme labeling method to evaluate the lipid peroxidation degree of zebrafish.The levels of superoxide dismutase(SOD),catalase(CAT),glutathione(GSH),and glutathione peroxidase(GSH-PX)were assayed by microenzyme labeling method to evaluate the antioxidant stress level of zebrafish.Tyrosine hydroxylase(TH)immunohistochemistry was used to evaluate dopaminergic nerve injury in zebrafish.The expressions of TH,nuclear factor E2 related factor(Nrf2),quinone oxidoreductase 1(NQO1),Heme oxygenase 1(HO-1),glutamate-cysteine ligase catalytic subunit(GCLC),and glutamate-cysteine ligase modified subunit(GCLM)were detected with western blot method to clarify the molecular mechanism of antioxidant stress.Results: Compared with the control group,the total distance,mean speed and maximum acceleration of zebrafish in MPTP model group significantly decreased(P <0.01),the absolute turn angle,angular velocity and immobility time of zebrafish during spontaneous movement significantly increased(P < 0.01),zebrafish of the MPTP model group showed an impairment of motor function.Compared with the MPTP model group,CA groups significantly improved the total distance,mean speed and maximum acceleration of zebrafish(P < 0.05 or P < 0.01);In addition,CA groups significantly reduced the absolute turn angle,angular velocity and immobility time of zebrafish during spontaneous movement(P < 0.05 or P < 0.01),CA improved the motor dysfunction in zebrafish.Compared with the control group,MPTP model group significantly increased the levels of ROS and MDA in zebrafish(P < 0.01);Compared with the MPTP model group,CA groups significantly decreased ROS and MDA levels in zebrafish(P < 0.05 or P < 0.01);In addition,compared with the control group,MPTP model group significantly reduced the levels of GSH and the activities of antioxidant enzymes SOD,CAT and GSH-Px(P < 0.01);Compared with the MPTP model group,CA groups significantly increased the levels of GSH and the activities of antioxidant enzymes SOD,CAT and GSH-Px in zebrafish(P < 0.05 or P < 0.01).Compared with the control group,MPTP model group significantly decreased the density of TH-positive neurons,Compared with the MPTP model group,CA groups significantly increased the density of TH-positive neurons in zebrafish.Compared with the control group,MPTP model groups significantly reduced the protein expressions of TH,Nrf2,NQO1,HO-1,GCLC,and GCLM in Zebrafish(P < 0.05 or P < 0.01),and CA significantly reversed these protein expressions compared with the MPTP model group(P < 0.05 or P < 0.01).Conclusion: CA can improve MPTP-induced motor dysfunction and reduce DA nerves injury in zebrafish.The neuroprotective mechanism of CA may be related to regulating Nrf2 signal pathway to inhibit oxidative stress.