Neuro-protective Effects Of Puerarin On Cell Model Of Parkinson’s Disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder. It is mainly characterized by a selective depletion of dopamine (DA) neurons in the substantia nigra (SN). For the treatment of PD, estrogen replacement therapy showed a good prospect. So that, it is a hot research to find the potential chemotherapeutic PD compounds. The phytoestrogen puerarin, the main isoflavone, can combine with the estrogen receptor (ER), then palys an estrogen-like effects.This study aimed to research the protective effect and the mechanism of puerarin on the cell model of Parkinson’s disease (PD). The main results are summarized as following.(1) The PD cell model was established by1-methyl-4-phenylpyridine (MPP+) induced PC12cells for48h, PC12cells were pretreated with puerarin for1h and then detected the protective effect. MTT assay showed that cell viability was maintained at about60%by0.05mM puerarin. Mitochondrial membrane potential (MMP), Caspase-3, Bcl-2and Bax assays found that the antiapoptosis effect of puerarin on PD was dependent on mitochondrial apoptosis pathway.(2) In order to research the puerarin anti-apoptosis mechanism, first, the green fluorescent protein (EGFP)-ERβ recombinant plasmid was successfully constructed. Second, HEK293T cells were transiently transfected with the pcDNA6-mERβ-EGFP plasmid, overexpression of ERβ, further the Caspase-3activity, Bcl-2and Bax expression were tested. These results showed that they were dependent on the expression of ERβ and blocked by the estrogen receptor antagonist ICI182,780. Finally, fractionation studies were conducted to determine the subcellular localization of ERβ in PC12cells and transfected HEK293T cells, the result showed that ERβ protein was observed in the nuclear fractions of PC12cells and transfected HEK293T cells. The localization of ERβ to the nuclear fractions suggested that it has the potential to impact genomic signaling pathways. The luciferase reporter assay showed that the transcriptional activity of ERβ was increased by puerarin.These results suggest that puerarin can protect PD cell model from apoptosis. The specific mechanism of puerarin may be related to the contained isoflavones, because isoflacones can bind to ERβ, and then regulate the transcription activity of the downstream target genes. Further it acts the estrogen replacement effect and inhibits apoptosis.