Effects of DHP on dyskinesia,neuronal damage and senescence of astrocytes in mice with Parkinson's disease

ZHANG Pei; DONG Jianjian; XU Chenchen; WANG Shijing; CHENG Nan

doi:10.3969/j.issn.1002-266X.2023.35.006

Abstract：Objective To study the effects of Dendrobium huoshanense polysaccharide(DHP)on dyskinesia,neu-ronal damage,and senescence of astrocytes in mice with Parkinson's disease(PD).Methods Forty male C57BL/6 mice were randomly divided into the NC group,MOD group,DHP100 group,and DHP350 group,with 10 mice in each group.PD mouse models were established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in the MOD,DHP100 and DHP350 groups.After the models were established,the DHP100 and DHP350 groups were given 100 mg/kg and 350 mg/kg of DHP by gavage of 0.5 mL,once a day,for 2 weeks,respectively.The motor abil-ity of each group was evaluated by the passing time of balance beam,the hanging time of suspension,and the staying time of rotating rod test;the fluorescence expression of mouse midbrain nigral tyrosine hydroxylase(TH)and astrocyte nuclear fibrillar protein B1(Lamin B1)was detected by immunofluorescence;the relative expression of midbrain Lamin B1,inter-leukin-1β(IL-1β),and interleukin-6(IL-6)proteins was detected by Western blotting,and the expression of midbrain p16INK4a and matrix metalloproteinase 3(MMP-3)mRNA was detected by real-time fluorescence quantitative PCR.Mouse astrocytes C8-D1A cells were divided into three groups.Cells in the normal group were cultured with serum-free DMEM medium,and cells in the model group were treated with 0.6 mmol/L 1-methyl-4-phenylpyridine ion(MPP+)for 24 h,while the cells in the DHP group were pretreated with 8 μg/mL DHP for 12 h and then were treated with 0.6 mmol/L MPP+ for 24 h.The cell supernatant of the three groups was collected as the conditioned culture medium to act on human neuro-blastoma cells(SH-SY5Y).The survival rate of SH-SY5Y cells,cell cycle ratio,positive rate of β-galactosidase(β-gal),and telomerase activity of the three groups were compared.Results Compared with the NC group,the staying time,hanging time and the number of TH-positive neurons in the midbrain and the relative expression of Lamin B1 protein de-creased in the MOD group,and the passing time and the relative expression levels of IL-1β,IL-6 protein and p16INK4a and MMP-3 mRNA increased(all P＜0.05).Compared with the MOD group,the staying time,hanging time,the number of TH-positive neurons and the relative expression levels of Lamin B1 protein in the DHP100 group and DHP350 group in-creased,while the passing time,IL-1β protein and MMP-3 mRNA relative expression levels decreased,and moreover,the changes in the staying time,passing time,IL-1β protein and MMP-3 mRNA relative expression levels were more signif-icant in the DHP350 group(all P＜0.05).The relative expression levels of IL-6 protein and p16INK4a mRNA in the DHP350 group were lower than those in the MOD group and DHP100 group,and the fluorescence expression levels of Lamin B1 in nigra astrocytes in the MOD group were lower than those in the NC group,DHP100 group and DHP350 group(all P＜0.05).After the addition of cell-conditioned medium,the survival rates of SH-SY5Y cells in the normal,DHP and model groups decreased sequentially,with statistically significant difference between groups(all P＜0.05).Compared with the normal group,the proportion of cells in the G0/G1 phase and the positive rate of β-gal increased,and the proportion of cells in the S phase and telomerase expression decreased in the model group(all P＜0.05);compared with the model group,the proportion of cells in the G0/G1 phase and the positive rate of β-gal decreased,and the proportion of cells in the S phase and telomerase expression increased in the DHP group(all P＜0.05).Conclusion DHP can alleviate the dyskinesia of PD mice,and the mechanism may be related to inhibiting the senescence of astrocytes,thus alleviating the damage of neu-rons and exerting neuroprotective effect.