Table 1.
Summary of probiotic studies in rodent models on anxiety and depressive-like behaviours and brain metabolism. ↑ increase, ↓ decrease.
| Model Organism (Paradigm) | Probiotic (Dose) | Duration of Treatment | Behavioural Effects | Neurochemical Effects | Reference |
|---|---|---|---|---|---|
| 7-week-old male BALB/c mice (healthy) |
B. longum 1714 or B. breve 1205 (1 × 109 CFU, daily) |
3 weeks prior to start of behavioural tests, 3 weeks during behavioural testing (6 weeks total) | ↓ anxiety (OFT, MBT) and ↓ depressive-like behaviour (FST) (B. longum 1714) ↓ anxiety (EPM and MBT) (B. breve 1205) |
Not applicable | [95] |
| 6-week-old male BALB/c mice (vagotomy) |
L. rhamnosus JB-1 (1 × 109 CFU, daily) |
4 weeks (behavioural assays started during final week of treatment) | ↓ anxiety (EPM, OFT) ↓ depressive-like behaviour (FST) |
Altered hippocampal GABAA receptor subunit expression, effects dependent on vagus nerve | [35] |
| 4-week-old male BALB/c mice (healthy MRI and MRS brain imaging) |
L. rhamnosus JB-1 (1 × 109 CFU, daily) |
4 weeks (imaging performed throughout duration of treatment at weeks 0, 1, 2, 3, 4, and 4 weeks post-treatment cessation) | Not applicable | ↑ brain Glx at weeks 2, 3, 4, 8 ↑ brain NAA at weeks 1, 2, 3, 4 ↑ brain GABA at week 4 only |
[96] |
| Male Swiss albino mice 25–30 g (28 days CMS) | L. plantarum MTCC 9510 (2 × 1010 CFU, daily) | 4 weeks (duration of CMS paradigm) | CMS ↓ locomotion (OFT), ↑ depressive-like behaviour (FST, TST), reversed by L. plantarum MTCC 9510 | CMS ↑ BBB permeability, ↑ brain NF-kB, reversed by L. plantarum MTCC 9510 | [97] |
| Male neonatal C57Bl/6 mice (maternal separation) | B. pseudocatenulatum CECT 7765 (1 × 108 CFU, daily) | 20 days (PND2 to PND21) | MS ↑ anxiety (EPM). B. pseudocatenulatum CECT 7765 ↓ anxiety (EPM) |
Not applicable | [98] |
| 4-week-old male Sprague Dawley rats (chronic HFD, 60% of kilocalories from fat) | B. bifidum W23, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, Lc. Lactis W19, Lc. Lactis W58 (3.75 × 108 CFU/mL in drinking water, daily) | 5 weeks prior to start of behavioural tests, 10 weeks total | Probiotic mixture ↓ depressive-like behaviour (FST) irrespective of diet. | Not applicable | [99] |