Intestinal toxicity evaluation of TiO2 degraded surface-treated nanoparticles: a combined physico-chemical and toxicogenomics approach in caco-2 cells

Table 2 Microarray results

Microarray Analyses	Total number of genes	Number of detected genes*	Number of genes up- or down- expressed (>1.5 fold change )	Number of genes significantly up- or down- expressed (pvalue < 0.05)**	% of genes altered out of detected spots
CTRL 2 vs CTRL 1	41000	23425	970	5	0,021%
Ti-Lite vs CTRL 1	41000	23828	419	1	0,004%
Ti-Lite DL vs CTRL 2	41000	22989	845	2	0,009%
Ti-Lite DA vs CTRL	41000	19928	824	0	0%
H₂O₂ vs CTRL	41000	28900	14651	9307	32,2%

Caco-2 cells were cultured and differentiated for 21 days. The cells were exposed for 72 h at 10 μg/mL of TiO₂ STNPs native or degraded. After mRNA extraction, labeled cDNA (Cy3) was hybridized to Agilent oligomicroarray (41 000 genes). The number of genes detected above a raw intensity threshold (background + 2SD) was compared for each type of STNPs exposed versus unexposed cells (*). From the remaining spots, we selected those with fluorescence ratios (representing STNPs exposed versus unexposed samples) greater than 1.5-fold change cutoff. Then we determined the statistical significance of the changes with pvalue ≤ 0.05 using a student t-test statistical analysis (n = 4) and performing a Benjamini and Hochberg false discovery rate multiple testing correction (**) using Genespring software. At the end of this analysis, we obtained lists of genes which were significantly induced or repressed after exposure to STNPs.

ISSN: 1743-8977