The Neuroprotective Effects And Anti-Apoptotic Mechanism Of Isorhamnetin-3-O-Glucoside On Dopaminergic Neurons In PD Models

BackgroundParkinson's disease(PD)is a central nervous system degenerative disease characterized by motor dysfunction.The main pathological characteristics of PD exhibit decreases in dopaminergic neurons in the nigrostriatal mesenteric striatum,which ultimately leads to the deficiency of dopamine(DA).Recent evidence shows that protecting the remaining neurons or reversing damaged neurons is the key to delay or stop disease progression.At present,the treatment of PD mainly focuses on increase in symptomatic DA content of the brain.Levodopa has long been the gold standard for the treatment of PD.However,with the prolongation of treatment time,a series of complications will o ccur in the treatment of PD with levodopa.Therefore,development of novel neuroprotective drugs for the treatment of PD has important clinical significance.ObjectivesTo investigate the molecular mechanism of isorhamnetin-3-o-glucoside inhibiting MPP~+-induced apoptosis in cells,And to explore the effect of isorhamnetin-3-o-glucoside on MPTP-induced ethlolgy in Parkinson's mice and apoptosis in dopaminergic neurons,so as to provide new ideas for the treatment of PD.MethodsCell viability was determined by MTT assay.Cell apoptosis was detected by using AnnexinV/PI staining and flow cytometry.The expression of diverse proteins was determined by Western blot analysis.Mitochondrial membrane potential was detected by JC-1 staining and flow cytometry.The colocalization of related proteins was determined by confocal laser scanning microscopy.ResultsIn vitro,pretreatment with isorhamnetin-3-O-glucoside significantly attenuatted MPP~+-induced cytochrome c release,caspase 3/caspase 9 activation,PARP degradation,as well as apoptosis.Furthermore,pretreatment with isorhamnetin-3-O-glucoside markedly abrogated MPP~+-induced mitochondrial fission and loss of mitochondrial membrane potential,and inhibited cell apoptosis through the PI3K/AKT signaling pathway.Mechanistically,we found that pretreatment with isorhamnetin-3-O-glucoside attenuated MPP~+-mediated dephosphorylation of Drp1(Ser637)and mitochondrial translocation of Drp1.In vivo,we found that pretreatment with isorhamnetin-3-O-glucoside attenuated MPTP-induced apoptosis in mouse dopaminergic neurons and decreases in TH immunoreactivity.Conclusion1.Isorhamnetin-3-o-glucoside regulate the expression of Drp1,which interacts with Bax,resulting in inhibition of MPP~+-induced mitochondrial fission,in turn to blockade of abrogating cell apoptosis.2.Isorhamnetin-3-o-glucoside can inhibit MPTP-induced injury in mice.