Isolated ileal interposition in enteroendocrine L cells differentiation

The method of analysing gene expression by real-time PCR proposed here represents a
relative quantification of genes of interest because it requires an endogenous control (a gene
whose expression does not exhibit statistically significant variation among the analysed
samples). Relative quantification of a given sample by real-time PCR results from the
relationship between the Ct of the gene of interest (i) and the Ct of the endogenous control
(e):
Nsi=Noi x 2 -Cti (gene of interest)
Nse=Noe x 2 -Cte (endogenous gene)
Because Nsi/Nse is equal to the normalised number of molecules of the gene of
interest relative to the number of endogenous control molecules that we will call X, and Nse
Nature Precedings : doi:10.1038/npre.2011.6614.2 : Posted 30 Nov 2011
and Nsi is a constant that we will name K, the equation becomes:
X=K.2 - Ct
Relative quantification of gene expression is used to describe changes in the
expression of a gene of interest in a group of samples relative to a control group. In this study,
we will compare ileum and jejunum samples in their normal localisations with interposed
ileum samples and with ileum samples from animals in the sham-treated group. Thus, the
value of X will be measured under two different conditions, and by dividing the value of X
under condition A by the value of X under condition B, we obtain 2 - Ct , as shown by the
following equation:
This method will be used in our study to calculate the relative expression levels of
genes of interest. The relative expression levels of genes of interest will be compared among
the different segments from different groups of animals (IG ileum, SG ileum, CG jejunum, and
ileum).
3.14.5. Statistical analysis
The variables will be summarised for each study group using the pertinent descriptive
statistics: absolute (n) and relative (%) frequency, or mean, standard deviation (s.d.), median,
maximum, and minimum values. The data will be analysed using parametric or non-parametric
tests according to the observed distribution.