DL-3-N-Butylphthalide Exerts Dopaminergic Neuroprotection Through Inhibition Of Neuroinflammation

Background:Microglia-mediated neuroinflammation plays vital role in the occurrence and development of PD(Parkinson's disease)and other neurodegenerative diseases.Recently the regulation of microglial activation has emerged as a novel strategy for PD therapy.Dl-3-n-butylphthalide(NBP),a drug mainly applied in treating patients with ischemic stroke,has drawn lots of attention due to its multiple neuroprotection effect including anti-inflammation and antioxidant activity.This study is aimed to determine whether NBP could suppress microglial activation and protect dopaminergic neurons from excessive neuroinflammation.Methods:1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD model was established to explore the neuroprotective and anti-inflammatory effect of NBP in vivo.We assessed motor deficits,measured dopamine level by high-performance liquid chromatography,evaluated dopaminergic neurodegeneration and microglial activation by immunohistochemical staining or immunofluorescence staining and determined related protein level by Western blot.In vitro,the anti-inflammatory activity of NBP was confirmed by cell viability assay of SH-SY5Y cells after being treated with conditioned medium from lipopolysaccharide(LPS)or1-methyl-4-phenylpyridinium iodide(MPP~+)-stimulated BV-2 cells.The expression of pro-inflammatory molecules was determined by RT-PCR,Western Blot and ELISA assay.The generation of nitric oxide(NO)and reactive oxygen species(ROS)were also assessed.The involvement of signaling pathways such as mitogen-activated protein kinase(MAPK),nuclear factor kappa-light-chain-enhancer of activated B cells(NF-?B),and PI3k/Akt were further investigated by Western Blot and immunofluorescence assay.Results:The neuroprotective effect of NBP was demonstrated in vivo as shown by the improvement of dopaminergic neurodegeneration,motor deficits and microglial activation in MPTP-induced mouse model of PD.The expression of pro-inflammatory mediators was also reduced by NBP administration.In vitro,NBP also protected dopaminergic neurons from neurotoxicity induced by activated microglia.NBP pretreatment not only reduced pro-inflammatory molecules,but also suppressed NO release and ROS generation in BV-2 cells.Further mechanism research suggested that the inactivation of MAPK,NF-?B and PI3K/Akt may involve in anti-neuroinflammation role of NBP.Conclusion:Our results revealed that NBP exerted dopaminergic neuroprotection through inhibition of microglia-mediated neuroinflammation,suggesting the promising therapeutic effect of NBP for PD.