Effects of endurance training on autophagy of substantia nigra neurons and secretion of plasma exosomes in Parkinson disease mice / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the protective effect of endurance training on Parkinson disease(PD) mice and the effect of AMPK/mTOR pathway on autophagy and exosomes secretion.Methods:Thirty-two 10-week-old male C57BL/6 mice were randomly divided into quiet group, exercise group, PD quiet group and PD exercise group, with 8 mice in each group.The mice in exercise group and PD exercise group received 4-week treadmill endurance training.After training, mice in PD quiet group and PD exercise group were given rotenone (30 mg·kg -1·d -1) dissolved in 0.5% carboxymethyl cellulose salt solution and gavaged for 56 consecutive days.The mice in quiet group and exercise group were given 0.5% carboxymethyl cellulose salt solution by gavage.Then, the mice in exercise group and PD exercise group received treadmill endurance training for 4 weeks.The behaviors of mice in each group were measured after training.The content of tyrosine hydroxylase (TH) in substantia nigra of mice in each group was measured by immunohistochemistry.Western blot was used to detect the expression of plasma α-synuclein(α-syn), exosomes surface marker proteins CD9 and CD63, and the content of microtubule associated protein light chain 3-Ⅱ (LC3-Ⅱ), α-syn, adenine ribonucleotide dependent protein kinase (AMPK) and phosphorylated AMPK (p-AMPK), mammalian target of rapamycin (mTOR) and phosphorylated mTOR (p-mTOR) in substantia nigra of mice in each group.SPSS 20.0 software was used to analyze the data.One-way ANOVA was used for comparison among multiple groups and the LSD method was used for further pairwise comparison. Results:There was significant difference in the residence time of mice in the four groups on the rotarod instrument ( F=2 618.20, P<0.01). Compared with the quiet group, the residence time of PD quiet group decreased ((110.34±8.20) s, (186.20±6.83) s, P<0.01). Compared with the PD quiet group, the residence time of PD exercise group increased ((160.56±8.30)s, P<0.01). (2) There was no significant difference in the expression of plasma exosome marker proteins CD9 and CD63 among the four groups ( F=1.57, 1.26, both P>0.05). (3) There was significant difference in the expression of α-syn in plasma exosomes of the four groups ( F=1 303.99, P<0.01). The expression of α-syn in plasma exosomes in PD quiet group was higher than that of quiet group ((180.57±8.20), (100.00±0.00), P<0.01). Compared with the PD quiet group, the expression of α-syn in plasma exosomes in PD exercise group decreased ((150.23±7.30), P<0.01). (4) There was significant difference in the number of TH positive neurons in substantia nigra among the four groups ( F=447.09, P<0.01). Compared with the quiet group, the number of TH positive neurons in the substantia nigra of PD quiet group decreased ((48.23±6.30), (100.00±0.00), P<0.01). Compared with the PD quiet group, the number of TH positive neurons in the substantia nigra of PD exercise group increased ((68.62±8.20), P<0.01). (5) Western blot showed that there were significant differences in the expression of α-syn, p-mTOR, p-AMPK and LC3-Ⅱ in substantia nigra of the four groups ( F=753.62, 361.48, 261.95, 248.07, all P<0.01). Compared with the quiet group, the expression of α-syn in substantia nigra of PD quiet group increased ((184.16±15.31), (100.00±0.00), P<0.01), the expression of p-mTOR in substantia nigra increased ((156.77±3.99), (100.00±0.00), P<0.01), the expression of p-AMPK decreased ((70.65±8.43), (100.00±0.00), P<0.01), and the expression of LC3-Ⅱ in substantia nigra decreased ((72.25±7.86), (100.00±0.00), P<0.01). Compared with PD quiet group, the expression of α-syn in substantia nigra decreased ((158.23±9.30), P<0.01), the expression of p-mTOR in substantia nigra decreased ((123.61±16.86), P<0.01), the expression of p-AMPK increased ((96.35±9.45), P<0.01), and the expression of LC3-Ⅱ in substantia nigra increased ((108.89±10.67), P<0.01). Conclusion:Endurance training regulates autophagy and the expression of exosomes in PD mice through AMPK/mTOR signal pathway, protects dopaminergic neurons in mouse midbrain and improves motor function.