Gut Microbial Alteration in MPTP Mouse Model of Parkinson Disease is Administration Regimen Dependent

Abstract

Parkinson Disease (PD) is one of the most common neurodegenerative disorders characterized by loss of dopaminergic neurons involved in motor functions. Growing evidence indicates that gut microbiota communicates with the brain known as the gut-brain axis (GBA). Mitochondrial toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is commonly used in animal studies to investigate the GBA in PD. Various MPTP administration regimens are performed in PD mouse models involving one to multiple injections in 1 day or one injection per day for several days. The aim of this study is to investigate if the impact of MPTP on gut microbiota differs depending on the administration regimen. C57BL/6 mice were treated with acute or subchronic regimens of MPTP. Motor functions were assessed by open-field, catalepsy, and wire hanging tests. The cecum and the brain samples were obtained for microbiota and gene expression analyses, respectively. MPTP administration regimens differed in their ability to alter the gut microbiota. Firmicutes and Bacteroidota were both increased in subchronic mice while did not change and decreased, respectively, in acute mice. Verrucomicrobiota was elevated in acute MPTP mice but dropped in subchronic MPTP mice. Muribaculaceae was the predominant genus in all groups but acute mice. In acute mice, Akkermansia was increased and Colidextribacter was decreased; however, they showed an opposite trend in subchronic mice. These data suggest that MPTP mouse model cause a gut microbiota dysbiosis in an administration regimen dependent manner, and it is important to take consideration of mouse model to investigate the GBA in neurodegenerative diseases including PD.

Keywords: Acute; Animal model; Microbiota; Subchronic.

Fig. 1

MPTP induced behavioral alteration of mice in the open-field locomotion test. Mice in acute regimen groups (A) were injected intraperitoneally (i.p.) 18 mg/kg MPTP-HCl four times at 2 h interval while the mice in subchronic regimen groups (B) were received (i.p.) 30 mg/kg MPTP-HCl daily for 5 consecutive days. Student’s t test for parametric data (day 0, day 2, and day 4 while Wilcoxon Mann–Whitney test was applied for nonparametric data (day 6) (C), representative examples of moving pattern from each group. White bar, Control; Patterned bar, MPTP *p < 0.05: significant differences from the control, (n: 6/group)

Fig. 2

MPTP induced behavioral alteration of mice in the catalepsy (A) and wire hanging (B) test. Mice in acute regimen groups were injected intraperitoneally (i.p.) 18 mg/kg MPTP-HCl four times at 2 h interval while the mice in subchronic regimen groups were received (i.p.) 30 mg/kg MPTP-HCl daily for 5 consecutive days. Wilcoxon Mann–Whitney test was applied. White bar, Control; Patterned bar, MPTP *p < 0.05: significant differences from the control, (n: 6/group)

Fig. 3

Fold change in gene expression of Tyrosine hydroxylase (Th), α-synuclein (α-syn), Dopamine Receptor 1 (Drd1), Dopamine Receptor 2 (Drd2), and Dopamine Transporter (Dat) in the striatum of mice administered MPTP or saline. Mice in acute regimen groups were injected intraperitoneally (i.p.) 18 mg/kg MPTP-HCl 4 times at 2 h interval while the mice in subchronic regimen groups were received (i.p.) 30 mg/kg MPTP-HCl daily for 5 consecutive days. Relative gene expression was calculated by 2^−ΔΔCt method by normalizing gene expression to β-actin. White bar, Control; Patterned bar, MPTP.(n: 4/group)

Fig. 4

MPTP administration altered the composition of cecal microbiome in mice at phylum level. A Microbial communities of individual mouse cecum content. B Predominant phylum in the cecum microbiome of mice administered MPTP (n: 5 for each bar). C Pair wise comparison of each group. Statistical p-values were assessed using a Monte-Carlo test with 10,000 replicates

Fig. 5

The microbiota composition of mouse cecum digesta at the genus level was clustered by MPTP administration regimen using between group analysis (BGA) (A). B Pair wise comparison of each group. Statistical p-values were assessed using a Monte-Carlo test with 10,000 replicates

Fig. 6

MPTP administration altered the composition of cecal microbiome in an application schedule-dependent manner. A Petal diagram represents the number of core genera and unique genera detected in Control and MPTP mice. B The major microbial communities of mouse cecum content at genus level in the control group and MPTP group. Only genera with over 3% of the total bacteria are presented (n: 5 for each bar)