Table 3.
Morphological transformation versus outcome in genotoxicity assays in Syrian hamster Embryo (SHE) cells treated with different forms of amorphous and crystalline silica
| Test material | Dose (μg/cm2) | MN1 (% of cells) 24 h |
Comet1 (% tail) + FPG, 24 h |
Morphological transformation frequency (%) |
|---|---|---|---|---|
| Control | 0 | 2.3 ± 0.5 | 13.0 ± 1.0 | 0.01 |
| Diatomaceous earth (DE) (GSD: 1.35 μm) |
3.81 | 0.02 | ||
| 7.62 | 0.02 | |||
| 11.4 | 11.0 ± 1.2 | |||
| 13.6 | 2.1 ± 0.8 | |||
| 15.24 | 0.11* | |||
| 22.8 | 18.0 ± 2.0 | |||
| 27.2 | 2.0 ± 0.6 | |||
| 30.48 | 0 | |||
| 45.7 | 21.0 ± 2.5 * | |||
| 54.4 | 1.8 ± 0.6 | |||
| Heated DE (see above), containing 47% Cristobalite (GSD: 4.85 μm) |
3.81 | 0.16* | ||
| 7.62 | 0.19* | |||
| 11.4 | 6.5 ± 1.5 | |||
| 13.6 | 3.0 ± 1.0 | |||
| 15.24 | 0.23* | |||
| 22.75 | 2.0 ± 0.6 | 9.0 ± 1.0 | ||
| 30.48 | 0.4* | |||
| 45.7 | 10.0 ± 4.5 | |||
| 54.4 | 1.8 ± 0.3 | |||
| Quartz Min-U-Sil 5 (GSD: 1.33 μm) |
3.81 | 0.24* | ||
| 7.62 | 0.17* | |||
| 11.4 | 9.8 ± 1.2 | |||
| 13.6 | 2.2 ± 1.3 | |||
| 15.24 | 0.71* | |||
| 22.8 | 11.0 ± 2.7 | |||
| 27.75 | 2.2 ± 1.3 | |||
| 30.48 | 0.77* | |||
| 45.7 | 8.0 ± 1.0 | |||
| 54.4 | 1.5 ± 0.3 |
1Data were estimated from graphical representations in Darne et al [24] (Figures. two A (MN) and Figures. three B (Comet), reproduced with permission). GSD Geometric mean diameter
* = statistically significant (p < 0.05) compared to control