Short-term oral administration of non-porous and mesoporous silica did not induce local or systemic toxicity in mice

Figures & data

Figure 1. DNA tail intensity (%) of jejunum samples from animals orally administered the vehicle (CTRL), the positive control MMS (100 mg/kg b.w.) or SAS particles and sacrificed at day 6 (A) or day 26 (B). LD: Low dose (100 mg/kg b.w). HD: High dose (1000 mg/kg b.w.). All values are means ± SEM (n = 6). (*) p < 0.05, one-way ANOVA followed by Dunnett’s test (SAS exposed groups vs. control vehicle group) or Mann–Whitney U-test (MMS vs. control vehicle group).

Table 1. Frequency of micronucleated cells [MNCs, mean (SD)] in 2000 normochromatic (NCEs) and polychromatic (PCEs) peripheral blood erythrocytes of vehicle [0.2% (w/v) CMC + 1% (v/v) Tween80 in MilliQ water], methylated (Me) non-porous (100 and 300 nm) and methylated porous (100 and 300 nm) SAS-treated and methyl methanesulfonate (MMS)-treated mice.

Time point, tissue Treatment	Dose (mg/kg bw/administration)	No. of animals	MNCs/2000 NCEs	MNCs/2000 PCEs	% PCEs in 500 erythrocytes
Day 6, peripheral blood
Vehicle control	–	8	–	4.38 (2.13)	3.40 (0.70)
100 nm	100	8	–	4.00 (2.00)	3.10 (0.90)
100 nm	1000	7	–	1.57 (2.23)	3.40 (1.20)
100 nm porous	100	8	–	3.50 (1.69)	3.60 (1.20)
100 nm porous	1000	8	–	2.75 (3.11)	4.10 (1.30)
300 nm	100	8	–	2.13 (1.46)	2.80 (0.60)
300 nm	1000	8	–	4.00 (4.38)	3.20 (1.50)
300 nm porous	100	8	–	2.50 (2.51)	3.10 (0.90)
300 nm porous	1000	8	–	2.57 (1.62)	3.40 (0.90)
MMS	100	8	–	37.50 (22.25)*	2.70 (1.60)
Day 26, peripheral blood
Vehicle control	–	8	4.63 (1.85)	1.63 (0.74)	3.40 (0.90)
100 nm	100	8	3.88 (1.46)	–	3.40 (0.80)
100 nm	1000	8	5.38 (2.50)	–	4.60 (1.80)
100 nm porous	100	8	5.00 (2.00)	–	4.10 (1.70)
100 nm porous	1000	8	5.00 (2.56)	–	4.30 (0.90)
300 nm	100	8	4.25 (2.82)	–	3.80 (1.10)
300 nm	1000	8	4.00 (1.31)	–	4.80 (1.30)
300 nm porous	100	8	3.25 (1.58)	–	4.30 (0.50)
300 nm porous	1000	8	4.63 (1.19)	–	4.20 (0.80)
MMS	100	8	6.50 (1.31)	23.75 (12.21)*	3.80 (1.60)

The proportion (%) of PCEs in 500 erythrocytes was determined to indicate possible toxicity. Samples were collected at day 6 and after a recovery period at day 26. Asterisks indicate significant differences to the corresponding control (*p < 0.01; Mann–Whitney U-test).

Figure 2. TNF-α levels in jejunal mucosa from animals orally administered the vehicle (CTRL) or SAS particles and sacrificed at day 6 (A) or day 26 (B). LD: Low dose (100 mg/kg b.w). HD: High dose (1000 mg/kg b.w.). All values are means ± SEM (n = 6). No statistically significant differences (p< 0.05) were observed by means of one-way ANOVA followed by Dunnett’s test .

Figure 3. Microscopy image from a jejunum section of a swiss female mouse treated with 1000 mg/kg b.w. 100 nm non-porous SAS. (B) Magnification of the image (A) white contour square area. (C) Image obtained with hyperspectral imaging microscopy from the same field of a consecutive jejunum section of image (A). Colored pixels indicate a spectral match with the RSL for 100 nm non-porous SAS. (D) Magnification of the image C white contour square area.

Figure 4. Percentage of matching pixels within the specified the tissue area of control and treated animals. HD: High dose (1000 mg/kg b.w.). All values are means + SEM (n = 7). Mann–Whitney U-test (**) p < 0.01.

Figure 5. Comparison of two material specific reference spectral libraries: obtained from a treated mouse or from the SAS stock dispersion. The hyperspectral microscopy images correspond to a jejunum section of a mouse treated with 1000 mg/kg b.w. 100 nm porous SAS from the follow-up group (26 days). (B) and (C) are magnifications of image (A) white contour square area, analyzed using a RSL obtained from jejunum sections of a treated mouse (B) or using a RSL obtained from the stock SAS dispersion (C).

Figure 6. Box-plots illustrating (A) Shannon diversity index and (B) phylogenetic diversity prior to the first administration and at day 6 for controls and SAS-treated groups. Median values and interquartile ranges have been indicated in the plots. Kruskal–Wallis pairwise test, (*) denotes p < 0.05.

Data availability statement

The data that support the findings of this study are mostly available within its supplementary materials. Any further data are available from the corresponding author [GJ], upon reasonable request.