Table 2.
Circadian rhythm investigation from sampling to data interpretation.
| Blood/Tissue/Serum | Biological process | |
|---|---|---|
| Time/Sampling | • Six points minimum over 24 h • Longitudinal sampling (conducted continuously over many cycles, preferably at regular intervals) or • Transverse sampling (sampling of many individuals, once per individual) |
|
| Experiments | Number of circulating immune cell | Temperature, blood pressure, wake/sleep cycle |
| ARN expression (clock genes) | ||
| Protein expression (clock protein) | ||
| Hormones or cytokines level | ||
| Bioluminescence monitoring (clock genes, temperature …) | ||
| Analysis | Cosinor and Cosinor fit Parameters: mesor, amplitude, phase, period |
|
| Statistical tests: Analysis of variance (ANOVA), Metacycle, CircaCompare, Fourier spectral analysis, Singular spectrum analysis (SSA)… | ||
| Interpretation | • Lack of expression • Lack of rhythm • Alteration of the rhythm (modification of one or more parameters) • Increase/decrease in mesor and/or amplitude • Shift/phase change • Lengthening/shortening of the period |
|