Study On The Protective Effects And Molecular Mechanism Of Dendrobine On MPP~+-induced Cell Models Of Parkinson's Disease

Parkinson's disease(PD)is the second most common neurodegenerative disorder,which has seriously threatened human health and quality of life.It closely associates with dopaminergic neurons loss in the substantia nigra.At present,some anti-PD drugs,such as levodoba,have been commonly used to improve the dyskinesia of PD patients.However,there are no drugs could be used to slow the ne urodegenerative process of PD.So it is urgent to develop new anti-PD drugs or functional foods with the function of protecting and repairing dopaminergic neurons to fundamentally treat or alleviate PD.Dendrobium is a precious edible Traditional Chinese Medicine,which has the effects of'tonifying stomach and promoting fluid,nourishing Yin and clearing heat,lightening body and extending life'.Modern pharmacological studies have shown that Dendrobium nobile alkaloids are important functional components for Dendrobium to play the role in nerve protection and nerve repair.Dendrobine(DDB)is the most representative characteristic alkaloids in Dendrobium,so it is of great significance to explore the potential nerve protection and nerve repair efficacy of DDB in the PD treatment.This paper uses MPP~+to induce the damage of SH-SY5Y cells and mice primary dopaminergic neurons to construct the PD cell models,and then investigates the protective effects and molecular mechanism of DDB.These results will be used to provide scientific basis for DDB application,and provide theoretical guidance for the further development of Dendrobium functional food.The contents and results of the study mainly include the following two aspects.(1)DDB has significant protective effects on the PD cell models.Evaluation of the activity of neurons by MTT,CCK-8 and LDH methods found that DDB could significantly increase the neuronal activity,inhibit LDH release,and thus improve the neurons damage.Hoechst/PI double staining analysis showed that DDB had a significant inhibitory effect on neuronal apoptosis.Western blot analysis showed that DDB could significantly inhibit the expression of apoptosis-related protein C leaved caspase-3 in neurons.The above results prove that DDB can inhibit apoptosis and improve damage,thereby exerting significant protective effects on the MPP~+-induced PD cell models.(2)DDB can protect the PD cell models by promoting the secretion of mesencephalic astrocyte-derived neurotrophic factor(MANF)and inhibiting endoplasmic reticulum stress(ERS).Western blot analysis of ERS signaling pathway showed that DDB could significantly inhibit the expression of BIP,p-e IF2?,ATF4,ATF6,XBP1S and C HOP in neurons,thus inhibiting the ERS response.RT-q PCR and western blot analysis showed that DDB could significantly increase the m RNA and protein expression levels of MANF in neurons.The above results indicate that DDB may inhibit ERS response by promoting the secretion of MANF,thus playing a protective role on the MPP~+-induced PD cell models.In summary,DDB has significant protective effect s on the MPP~+-induced PD cell models,which may be achieved by promoting the secretion of MANF in neurons and then regulating ERS signaling pathway to inhibit neuronal apoptosis.