The prairie vole gut–brain–microbiota axis: a narrative review
This narrative review proposes the prairie vole (Microtus ochrogaster) as an underutilized preclinical model for the microbiota–gut–brain axis under social stress, but generates no original experimental data and establishes no causality.
| Outcome | Grade | Direction | Effect | Studies |
|---|---|---|---|---|
| Construct validity of the model for pair bonding and biparental care | C | ▲ Favorable | Narrativo; sem tamanho de efeito quantificado | — |
| Role of oxytocin in partner preference | C | — Neutral | OTR knockout ainda forma par-bond (Berendzen et al. 2023); evidência conflitante | — |
| Role of vasopressin (V1aR) in male partner preference | C | ▲ Favorable | Bloqueio V1aR prejudica preferência por parceiro; sem IC reportado | — |
| Effect of social stress on prairie vole gut microbiota | D | — Insufficient | Dados preliminares sem sistematização; sem tamanho de efeito | — |
| Stress-induced intestinal permeability in the vole model | D | — Insufficient | Postulado mecanicista; sem dados experimentais controlados no modelo | — |
Context
The microbiota–gut–brain axis (MGBA) is a plausible mechanistic framework linking social stress, intestinal permeability, and behaviour. Conventional rodent models lack the quasi-monogamous pair bonding and biparental care seen in humans. Prairie voles display these rare social traits, offering higher construct validity for socially relevant MGBA research.
What the study showed
The review synthesises indirect evidence: (1) central oxytocin facilitates partner preference in females, but OTR-knockout voles still form pair bonds (Berendzen et al., 2023), challenging the necessity of this pathway; (2) V1aR blockade in the ventral pallidum impairs partner preference in males; (3) preliminary data suggest gut microbiota differs between paired and isolated prairie voles, but sample sizes and designs are not systematised; (4) stress-induced intestinal permeability is proposed as a mechanism without controlled trials in this model. No absolute effect sizes or 95% CIs are generated by the review itself.
How it was done
Unsystematic narrative review without a registered protocol, explicit search strategy, or formal risk-of-bias assessment (AMSTAR-2 not applicable). Covers approximately 45 years of prairie vole ecology, neurobiology, and microbiota literature. No original sample size.
Effect magnitude
No consolidated effect size is presented. Cited primary studies report behavioural effects (partner preference, stranger-directed aggression) in typically small samples (n = 8–20 per group), with no meta-analysis.
Limitations
Narrative review without systematic inclusion/exclusion criteria (AMSTAR-2 formally inapplicable; high risk of selection and publication bias). Extrapolation to humans requires extreme caution due to phylogenetic, dosing, and controlled-environment differences. The gut microbiota section is the least developed, with few original studies and no standardised taxonomic composition data. Individual primary studies cited have small samples and variable protocols.
In clinical practice
This review does not support any change in clinical practice. Clinicians should treat the findings as hypothesis-generating: the MGBA under social stress is biologically plausible but lacks human intervention evidence derived from this model. Await controlled experimental studies in the vole model before extrapolating.
What is still missing
Controlled experimental studies in prairie voles are needed that directly manipulate the microbiota (e.g., antibiotics, faecal transplant) and measure behavioural and intestinal permeability outcomes with adequate comparator groups and sample sizes sufficient for statistical power analysis.