Characterization of the gut microbiota in leptin deficient obese mice - Correlation to inflammatory and diabetic parameters.

Gut microbiota have been implicated as a relevant factor in the development of type 2 diabetes mellitus (T2DM), and its diversity might be a cause of variation in animal models of T2DM. In this study, we aimed to characterise the gut microbiota of a T2DM mouse model with a long term vision of being able to target the gut microbiota to reduce the number of animals used in experiments. Male B6.V-Lep(ob)/J mice were characterized according to a number of characteristics related to T2DM, inflammation and gut microbiota. All findings were thereafter correlated to one another in a linear regression model. The total gut microbiota profile correlated to glycated haemoglobin, and high proportions of Prevotellaceae and Lachnospiraceae correlated to impaired or improved glucose intolerance, respectively. In addition, Akkermansia muciniphila disappeared with age as glucose intolerance worsened. A high proportion of regulatory T cells correlated to the gut microbiota and improved glucose tolerance. Furthermore, high levels of IL-10, IL-12 and TNF-α correlated to impaired glucose tolerance, blood glucose or glycated haemoglobin. The findings indicate that gut microbiota may contribute to variation in various disease read-outs in the B6.V-Lep(ob)/J model and considering them in both quality assurance and data evaluation for the B6.V-Lep(ob)/J model may have a reducing impact on the inter-individual variation.

Family relationship of female breeders reduce the systematic inter-individual variation in the gut microbiota of inbred laboratory mice.

The gut microbiota (GM) may influence disease expression in several animal models for inflammatory diseases. It may therefore seem reasonable to pursue reduction in the number of animals used for individual studies by reducing the variation in the GM. Previous studies have shown that the composition of the GM is related to genetics to a certain extent. We hypothesized that the GM similarity in a group of mice born by mothers not being sisters would be lower than that in a group born by mothers being sisters. The lower similarity could lead to clustering of the GM of mice born by non-sisters according to their mothers, while such clustering would not be visible if the mothers were sisters. We used 16S rRNA gene (V3 region) polymerase chain reaction-derived amplicon profiling by denaturing gradient gel electrophoresis (DGGE) to study the GM composition in caecum samples of 33 eight-week-old C57BL/6Sca mice from a breeding set-up with dam breeders that were sisters, as well as caecum samples of 35 eight-week-old C57BL/6Sca mice from a breeding set-up with dam breeders that were not sisters. Principal component analysis revealed a significant difference between the litters from the breeding set-up with dam breeders that were not sisters, whereas no significant difference between the litters based on the breeding set-up with dam breeders that were sisters was observed. The results obtained indicate that the systematic variation in the GM of inbred mice can be reduced by increasing the family relatedness of the breeding pairs.