Neuroprotective Effects Of Piperine On The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-in Duced Parkinson's Disease Mouse Model

Aims: Parkinson's disease(PD)is second only to Alzheimer's disease as a neurodegenerative disorder among the middle-aged and elderly people.Moreover,there is no current effectively therapy of the disease is available.O xidative stress,inflammation,apoptosis play important roles among the numerous potential mechanisms of the onset of this disease.Piperine is the pharmacological active ingredients in pepper that has been proved various pharmacological effects.It's worthy to explore whether it can protect dopamine(DA)neurons.This study is designed to explore the neuroprotective effects of piperine on PD's mouse model and the possible mechanisms,aiming at providing new thought of therapy and experimental bases for PD.Methods: 1.The experimental C57BL/6 mice were randomly divided normal saline-treated controls(NS),the group treated with MPTP alone(MPTP)and piperine-treated 10 mg/kg body weight MPTP-induced group(P+M).Animals received repeated intraperitoneal injections(i.p.)of MPTP(30mg/kg)solution for 7 days.Piperine(10mg/kg)was administrated orally for 15 days including 8 days of pretreatment.Normal saline was used to control.2.15 days later,motor behavior analysis was conducted with the rotarod test.The Morris water maze(MWM)was used to test the cognitive learning ability of the mice.3.After the mice were sacrificed,using a thiobarbituric acid reactive substances assay kit to measure the activity of the lipid peroxidation product MDA,SOD activity was determined by using an SOD assay kit.The level of TH?IBa-1?IL-1? in the substantia nigra of mice's midbrain was observed by Immunohistochemical staining and Western blot.Results: 1.TH-positive cells were significantly decreased in the substantia nigra pars compacta(SNpc)after MPTP administration.2.Pretreatment with piperine can extended the length of time of the PD mice on the rotating rod.The mean escape latencies of the Piperine group was significantly shorter than the MPTP group.3.Piperine significantly increased SOD and prevented MDA activity in the mouse midbrain samples.Activated microglia and the expression of IL-1? were also obviously alleviated by piperine pretreatment and the ratio of Bcl-2/ Bax was increased.Conclusion: 1.PD mouse model can be successfully made by intraperitoneal injection of MPTP.2.Piperine can improved the motor coordination and the cognitive learning ability of the mouses.3.Piperine exerts a neuroprotective effect on dopaminergic neurons via antioxidant,anti-inflammatory and anti-apoptotic mechanisms in mouse model of Parkinson's disease.4.Based on above results,we suggest piperine has promise as a neuroprotectant for PD.It is valuable to further research.