Toxicity evaluation of manufactured CeO2 nanoparticles before and after alteration: combined physicochemical and whole-genome expression analysis in Caco-2 cells

Table 1 Microarray results

Microarray Analyses	Number of detected genes	Number of genes up/down- regulated (>1.5 fold change )	Number of genes significantly up/ down- regulated (pvalue < 0.05)	% of genes altered out of detected spots
CTRL 2 vs. CTRL 1	23425	970	5	0.02%
NB vs. CTRL 1	33312	1036	13	0.04%
NB-DL vs. CTRL 1	23962	1773	344	1.44%
NB-DA vs. CTRL 2	22892	2079	428	1.87%
Pristine CeO2 vs. CTRL 3	33023	6020	1643	4.98%
H₂O₂ vs. CTRL 3	28900	14651	9307	32.2%

Caco-2 cells were cultured and differentiated for 21 days. The cells were exposed for 72 h to 21.25 μg/mL CeO₂ NPs, surface-treated or degraded (n = 2). Pristine CeO₂ NPs at the same concentration and H₂O₂ (20 μM) were used as positive controls. After mRNA extraction, labeled cDNA (Cy3) was hybridized (n = 4) to an Agilent oligomicroarray (4 × 44,000 probes). The number of genes detected above the signal threshold was compared for each type of NP versus their own control. From these remaining spots, we selected those with fluorescence ratios (representing NP-treated samples versus untreated samples) above 1.5-fold change. Out of these spots, we selected those satisfying Benjamini-Hochberg multiple testing corrections. At the end of this analysis, we obtained lists of genes that were significantly induced or repressed after exposure to NPs.

ISSN: 1471-2164