TABLE 2.
Summary of recent pre- and probiotic studies in animal models of Parkinson’s disease.
| Study design | Sample size | Pre/probiotic | Frequency of use | Main findings | Author and year |
| Randomized controlled trial | 15 male C57BL/6 mice with 6-OHDA lesions; 15 male C57BL/6 mice with no lesions | 270 μl of SLAB51 (Streptococcus thermophilus, Bifidobacterium longum, B. breve, B. infantis, Lactobacillus acidophilus, L. plantarum, L. paracasei, L. delbrueckii subsp. bulgaricus, L. brevis) | Once per day for 2 weeks | Counteraction of 6-OHDA-induced effects; ↓ neuroinflammation | Castelli et al., 2020, p. 5 |
| Randomized placebo-controlled trial | 10 MitoPark PD mice in treatment group; 10 MitoPark PD mice in placebo group | 1010 CFU of Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus rhamnosus, Lactobacillus rhamnosus GG, Lactobacillus plantarum LP28, Lactococcus lactis subsp. lactis | Once per day for 16 weeks | ↑ Motor coordination, preservation of TH+ cells in SNpc; ↓ gait instability | Hsieh et al., 2020 |
| Randomized placebo-controlled trial | 10 male Wistar rats in probiotic and 6-OHDA arm; 10 male Wistar rats in 6-OHDA arm; 10 male Wistar rats in placebo/control arm; | 2 × 109 CFUs each ofLactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus reuteri, Lactobacillus fermentum | Once per day for 2 weeks | ↑ Rotational behavior and cognitive function; ↓ lipid peroxidation and neuronal damage | Alipour Nosrani et al., 2021 |
| Randomized placebo-controlled trial | 8 groups (7 male C57BL/6 mice each): treatment and placebo groups for each individual probiotic strain, treatment and placebo groups for 3-strain mixture | 8 ± 2 × 108 CFU/mL each of Lactobacillus plantarum CRL 2130, Streptococcus thermophilus CRL 807, Streptococcus thermophilus CRL 808 | Once per day for 3 weeks | ↑ Motor skills, TH+ cell counts, IL-10 counts in serum/brain tissue; ↓ IL-6 and TNF counts in serum | Perez Visñuk et al., 2020 |
| Randomized placebo-controlled trial | 26 C57Bl6/J male mice in probiotic group; 26 C57Bl6/J male mice in dextran sodium sulfate group; 26 C57Bl6/J male mice in placebo group | VSL#3®: 5.4 × 109 CFU of Streptococcus thermophilus, Bifidobacterium breve, B. lactis, Lactobacillus acidophilus, L. plantarum, L. paracasei, L. helveticus | Once per day for 4 weeks | ↓ LPS- and paraquat-induced weight loss | Dwyer et al., 2021 |
| Randomized placebo-controlled trial | 6 groups (12 male C57BL/6 mice each): MPTP only, probiotic (107 CFU) prior to MPTP, probiotic (107 CFU) and MPTP simultaneously, probiotic (109 CFU) prior to MPTP, probiotic (109 CFU) and MPTP simultaneously, placebo group (no MPTP or probiotics) | 107 or 109 CFUs of engineered probiotic (MG1363-pMG36e-GLP-1) that continually expresses GLP-1 (Chen et al., 2018) | Once per day for 1 week (pre- treatment groups); Once per day for 14 days (treatment for entire study period) | ↓ MPTP-induced locomotor impairments, microglia and astrocyte activation, expression of inflammatory cytokines, enteric Enterobacteriaceae; ↑ TH+ neurons, enteric Lactobacillus and Akkermansia | Fang et al., 2019 |
| Randomized placebo-controlled trial | 5 male C57BL/6 mice in probiotic and saline group; 5 male C57BL/6 mice in probiotic and MPTP group; 5 male C57BL/6 mice in placebo and saline group; 5 male C57BL/6 mice in placebo and MPTP group; | Novarex®: 2 × 106 CFU of Lactobacillus rhamnosus (L-GG), Bifidobacterium animalis (BB-12), Lactobacillus acidophilus (LA-5) in a commercial mixture | Once per day for 30 days | ↓ MPTP-induced neurotoxicity of dopaminergic neurons, expression of MAO B and MPP+ in striatum, glial activation, behavioral impairments ↑ butyrate levels in brain, expression of BDNF and GDNF in SN | Srivastav et al., 2019 |
| Randomized placebo-controlled trial | 6 groups (146 male C57BL/6 mice total): placebo/saline only (N = 36), saline and probiotic (N = 32), saline and non-viable probiotic (N = 5), MPTP only (N = 36), MPTP and probiotic (N = 32), MPTP and non-viable probiotic (N = 5) | 109 CFUs of Bifidobacterium breve strain A1 [MCC1274] (B. breve A1) | Once per day for 4 days | ↑ Hippocampal synaptic plasticity, expression of postsynaptic density protein-95 and synaptophysin, CA1 spine density; ↓ expression of neuropsin (OPN5), fear response | Ishii et al., 2021 |
| Randomized placebo-controlled trial | 6 groups (35 male Sprague-Dawley rats total): non-PD and placebo only (N = 5), untreated PD (N = 5), L-DOPA treated PD (N = 5), probiotic treated PD (N = 5), nutrient media treated PD (N = 5), probiotic and nutrient media treated PD (N = 5) | 1011 CFUs of Lactobacillus salivarius subsp. salicinius AP-32 | Once per day for 8 weeks | ↓ Dopaminergic neuron loss, loss of TH+ cells in striatum and SNc, weight loss ↑ locomotor speed and stride length, mitochondrial function, antioxidative enzyme activity (GPx and SOD), fecal SCFA concentration | Nurrahma et al., 2021 |
| Randomized placebo-controlled trial | 12 adult male Sprague-Dawley rats in probiotic group; 10 adult male Sprague-Dawley rats in 6-OHDA and probiotic group; 9 adult male Sprague-Dawley rats in 6-OHDA and placebo group; | 109 CFUs of Lactobacillus rhamnosus HA-114 |
Once per day for 6 weeks | ↓ Hippocampal-dependent cognitive deficits | Xie and Prasad, 2020 |
| Randomized placebo-controlled trial | 10 male C57BL/6 mice in MPTP group; 10 male C57BL/6 mice in MPTP and probiotic group; 10 male C57BL/6 mice in control/placebo group |
5 × 108 CFU of Clostridium butyricum strain WZMC1016 | Once per day for 4 weeks | ↓ Motor deficits, dopaminergic neuron loss, synaptic dysfunction, microglial activation; ↑ levels of colonic GLP-1 and GPR41/43, expression of cerebral GLP-1R | Sun et al., 2021 |