FTIR spectra were recovered from the OPUS software version 6.5 (Bruker Optics GmbH, Ettlingen, Germany) and transferred to MS Excel. Principal Component Analysis (PCA) and Significant Wavelengths Analysis (SWA) were performed in an R environment. SWA was employed to select the FTIR spectral regions with statistically significant differences in the comparison between the spectra of parental and MSCs cultures from the different experimental conditions tested [35 (link)]. In addition, pairs of spectra, each with three replicates, were compared using the Student’s t-test for each wavelength separately. For each wave number, the calculated p-value was recorded. Significant wavelengths were selected based on p < 0.01. Hierarchical cluster analysis was performed with MetaboAnalyst 5.0 [36 (link)]. Data were filtered based on interquartile range, normalized to the sample median, and scaled by Pareto scaling. Hierarchical cluster analysis (HCA) was employed to highlight the metabolic differences under stress between MSCs and PS cultures, using the Euclidean correlation method and the ward.D clustering algorithm. Significant wavelengths were selected based on these criteria: t-test (p adjusted < 0.05) and one-way ANOVA (p-value < 0.05).
Free full text: Click here
