| Parkinson’s disease(PD)is a neurodegenerative movement disorder that is caused by a selective loss of dopaminergic neurons,which is selectively sensitive to people over 55 years old.The clinical symptoms of PD include resting tremor,bradykinesia,muscle rigidity,and postural instability.With the aging of China,the incidence of Parkinson’s disease is increasing.Current PD treatments provide symptomatic relief but do not prevent or decelerate disease progression.Besides protein and nucleic acid,sugar is another important biological molecule.It plays an important role in cell division,differentiation,growth and metabolism.Laminaria japonica polysaccharides and porphyra polysaccharides are two kinds of acid heteropolysaccharide extracted from seaweed.Previous studys have shown that these two kinds of polysaccharides have many biological activities,such as antioxidant,anti-aging,anti-tumor,immunity enhancement and protection of dopamine neurons from injury.However,the complex structure of polysaccharides has caused difficulties in studying their neuroprotective mechanism.The aim of this study was to obtain glucuronomannan oligosaccharides and porphyra oligosaccharides to explore the mechanism of neuroprotective activity.The PD model is an important tool for studying its pathogenesis and screening drugs.The mouse model induced by MPTP has similar characteristics in pathological changes and behavior.6-OHDA is a DA neurodestructive agent,which can be metabolized by dopamine in the brain,and damage neurons by producting free radicals,reflecting the changes of cells with external stimulation.In this study,the neuroprotective mechanism of glucuronomannan oligosaccharides and porphyra oligosaccharides against MPTP was studied by behavioral,immunohistochemistry,western bloting and electrochemical HPLC.Furthermore,we also applied cell activity,apoptosis and mitochondrial membrane potential in 6-OHDA-induced PC12 cells and LPS-induced BV2 cells.(1)We obtained the glucuronomannan oligosaccharides from Laminaria japonica through acid hydrolysis.After analysis by HPLC,NMR and MS,we obtained two oligosaccharides with the degree of polymerization of 2 and 4,named GM1 and GM2.In vitro,GM1 and GM2 significantly improved cell viability and inhibited 6-OHDA-induced apoptosis.Furthermore,GM1 and GM2 improved the mitochondrial membrane potential(MMP)and inhibited the production of ROS.In vivo,MPTP was intraperitoneally injected for 7 days to induce PD.GM1 and GM2 treatment ameliorated behavioural deficits in MPTP-induced Parkinson’ mice.GM1 and GM2 inhibited the loss of DA and tyrosine hydroxylase(TH)in stritum and substantia nigra and protected dopaminergic neurons from injury.Furthermore,GM1 and GM2 up-regulated the PI3K/Akt signalling pathway to promote neuronal survival.(2)OP was prepared by acid hydrolysis of porphyran.The degree of polymerization of OP ranged from 2 to 13.OP was mainly composed of sulfated galactans and oligosaccharides with a linear backbone of alternating 3-linked β-D-galactose and 4-linked α-L-galactose-6-sulfate.In vitro,OP significantly restrained the overproduction of reactive oxygen species(ROS)and alleviated the MMP loss,with good free radical scavenging ability.Moreover,OP inhibited the activation of BV2 cells induced by LPS and restrained the production of cytokines and NO.In vivo,the behavioral deficits in spontaneous motor activity,latency to descend in a pole test,and suspension in a traction test were ameliorated after OP treatment.Additionally,we found that OP protected dopaminergic neurons from apoptosis.Glucuronomannan oligosaccharides(GM1and GM2)and oligo-porphyran(OP)possessed neuroprotective effects in vivo and in vitro.GM1 and GM2 mainly inhibited DA neurons from apoptosis,and OP also inhibit nerve inflammation.These two types of algal oligosaccharides with remarkedly anti-PD acitivity and simple structure,might provide new ideas for drug screening of Parkinson’s disease. |
