Tetrahydroxysilane

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Justification for type of information:

See Attached Justification

Cross-reference

Reason / purpose for cross-reference:

read-across source

Reference

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

other: Read Across Source

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

yes

Type of assay:

in vitro mammalian cell gene mutation test using the Hprt and xprt genes

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Test concentrations with justification for top dose:

The two colloidal samples Col 15 and Col 40/80, which were purchased at initial concentrations of 381 and 369 mg mL1, respectively, were not sonicated.
Serial dilutions of all SAS were prepared in 0.05 wt% BSA–water (0.655, 1.31, 2.62 and 5.25 mg mL1). An aliquot of each of these preparations was immediately diluted 10 times in the cell culture medium, leading to final SAS concentrations of 66, 131, 262 and 525 mg mL1.

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Details on test system and experimental conditions:

Mutation induction was assessed at the HPRT locus in
V79 cells by 6-thioguanine selection, as described by
the OECD 476 guideline. In 10 mL of culture
medium, 1 106 cells were seeded in 100-mm culture
dishes (55 cm2) 24 h prior to treatment. The cells
were then treated for 24 h with 1 mL of culture
medium (medium alone for the control, medium containing
SAS dilutions or medium containing ethyl
methanesulphonate (EMS), Sigma-Aldrich, at 400
mM as a positive control according to the OECD
476 guideline). Cells were harvested at the end of
treatment and aliquots of 1 105 cells were grown for
6 days in new plates, during which time the cells were
passaged once. Cells were then harvested and seeded
in ten 100-mm culture dishes (2 105 cells/dish) in
the presence of 6-thioguanine (6-TG, 5 mg mL1,
Sigma-Aldrich) and in ten 60-mm culture dishes (100 cells/dish) in the absence of 6-TG. Cultures
without 6-TG were grown over 7 days and those with
6-TG were grown over 10 days. The cell cultures were
then washed in PBS, fixed in ethanol for 15 min,
stained with 10% Giemsa (Merk, Germany) for 15
min and then scored. The percentage of surviving
cells (the cloning efficiency) was determined by
dividing the number of colonies scored by the number
of cells seeded without 6-TG. HPRT mutant frequency
per 106 surviving cells was calculated using
the cloning efficiency and the number of cells seeded
for mutation selection with 6-TG.

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Tetrahydroxysilane

EC Number:

233-477-0

EC Name:

Tetrahydroxysilane

Cas Number:

10193-36-9

Molecular formula:

H4O4Si

IUPAC Name:

silicic acid

Test material form:

solid

Results and discussion

Test results

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified