BEHAVIORAL AND NEUROPHYSIOLOGICAL PHENOTYPING OF THE WILDLING MOUSE MODEL

Wildling mice are a novel mouse model generated by transferring C57BL/6 embryos into wild-mouse surrogate mothers, resulting in offspring that combine a standard laboratory genetic background with a complex, natural microbiome. Due to their more mature immune system, Wildling mice have been proposed as a potentially more translationally relevant alternative to SPF mice. This study is part of a broader effort to systematically evaluate the suitability of Wildling mice for experimental research by comprehensive phenotypic characterisation in comparison to SPF mice.
The present study focuses on the behavioural and neurophysiological characterisation of Wildling and SPF mice. Animals were subjected to standardised behavioural paradigms relevant to affective, exploratory, and cognitive domains. In addition, home-cage activity was continuously recorded using an RFID-based tracking system. Faecal samples were collected longitudinally for the analysis of corticosterone metabolites and microbiome composition. At 20 weeks of age, blood samples and spleens were obtained for immune phenotyping, while brains were collected for neurophysiological analyses, including assessments of hippocampal neurogenesis and dendritic complexity of hippocampal neurons.
Preliminary analyses reveal minor differences between Wildling and SPF mice across behavioural paradigms and lower corticosterone metabolite levels in Wildling mice. Wildling mice also exhibited lower body weights than SPF controls, suggesting differences in baseline activity; corresponding analyses are ongoing. Histological and neurophysiological analyses are pending and will be presented at the conference. Overall, these data contribute to a nuanced evaluation of Wildling mice, indicating potential relevance to immunological research while highlighting practical considerations for their use in standard animal facilities.