Fig. 1

LIP-SP exacerbates motor dysfunction and dopaminergic neuronal loss in MPTP-induced PD mice. A Schematic illustration of the experimental procedure. MPTP, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. LIP, ligature-induced periodontitis. SP, subgingival plaque. LIP-SP, ligature-induced periodontitis with application of subgingival plaque. B Bar plots of performance in behavioral tests, including rotarod test and traction test. n = 5:5:10:10. C-D Representative immunohistochemical staining (C) and quantification (D) of tyrosine hydroxylase (TH)-positive fibers in striatum (ST). n = 5:5:5:5. E–F Representative immunohistochemical staining (E) and quantification (F) of TH-positive neurons in substantia nigra (SN). n = 5:5:5:5. Scale bar: 200 μm. G Western blotting analysis and quantification (H) of TH in ST. n = 5:5:5:5. I Representative immunofluorescence staining of dopaminergic neuron marker TH (red) and microglia marker Iba-1 (green) in SN. DAPI: 4’,6-diamidino-2-phenylindole dihydrochloride. J Quantitative analysis of the number of microglia in SN. n = 5:5:5:5. Scale bar: 200 μm.Values are expressed as mean ± SEM (standard error of the mean). Two-way ANOVA followed by Tukey’s multiple comparison test was used for statistical analysis. ns, not significant. *P < 0.05, **P < 0.01