http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2894525/


Establishment of a humanized mouse gut microbiota from frozen samples

We next determined whether humanization with a frozen fecal sample would result in similar diversity as colonization with a fresh sample. Therefore, ten 10 week-old germ-free C57BL/6J mice were colonized with the same fecal sample used for the initial humanization except that it had been stored at −80°C for over one year. Five weeks after colonization, half of the mice were switched to the Western diet and sacrificed 2 weeks later (N=5 mice/group) (study design illustrated in fig. 1C). Fecal microbial community structure was monitored in all recipients using multiplex V2-directed 16S rRNA gene pyrosequencing, beginning 8h after colonization (N=92 samples; table S5).
Fecal samples obtained from recipients 8h after inoculation had low diversity (fig. S2B), clustered separately (fig. 2A and fig. S3), and had a higher representation of Erysipelotrichi (47.97±1.99% of 16S rRNA sequences; fig. 2B) compared to recipients of the fresh sample. However, as with humanization using the fresh sample, the microbiota stabilized after 7d, with a level of diversity approaching that of the donor (fig. 2A,B and fig. S2B). All bacterial phyla, 11/12 bacterial classes, and 85% (56/66) of genus-level taxa detected in the frozen donor sample were found in the recipient mouse population (tables S3 and S4). Of the ten genus-level taxa that were missing from the humanized mice, one was found at 0.1% relative abundance in the original donor sample (Firmicutes; Clostridia; Clostridiales; Veillonellaceae; Acidaminococcus) and the rest were all at low abundance in the sample (0.006% on average). Switching mice to a Western diet significantly increased the Erysipelotrichi and significantly decreased the Bacteroidetes; these changes were evident within 1d day of the diet switch (fig. 2A,B; table S3). Our results show that it is possible to humanize germ-free animals by using frozen fecal samples.