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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1998-10-20 to 1998-12-10
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP. The original study was considered reliability 1. Read-across to the registered substance is considered scientifically justified and is reliability 2.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report date:
1999

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Version / remarks:
1997
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Constituent 1
Reference substance name:
3-aminopropyltriethoxysilane
EC Number:
213-048-4
EC Name:
3-aminopropyltriethoxysilane
Cas Number:
919-30-2
IUPAC Name:
3-(triethoxysilyl)propan-1-amine

Method

Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbital and Beta-Naphthoflavone induced rat liver S9
Test concentrations with justification for top dose:
200, 600, 1800, 3000, 5000 µg/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: culture medium
- Justification for choice of solvent/vehicle: homogeneous (as determined by visual inspection)
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Ham's F12 medium with 2 mM Glutamine, 100 IU/ml Penicillin, and 100 µg/ml Streptomycin
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without activation

Migrated to IUCLID6: 300 µg/ml
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Ham's F12 medium with 2 mM Glutamine, 100 IU/ml Penicillin, and 100 µg/ml Streptomycin
True negative controls:
no
Positive controls:
yes
Positive control substance:
3-methylcholanthrene
Remarks:
with activation

Migrated to IUCLID6: 10 µg/ml
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium;

DURATION
- Exposure duration: 4 hours (with and without activation)
- Expression time (cells in growth medium): 9 days
- Selection time (if incubation with a selection agent): 9 days
- Fixation time (start of exposure up to fixation or harvest of cells):


SELECTION AGENT (mutation assays): H 10 medium

NUMBER OF REPLICATIONS: triplicate plates, experiment repeated

NUMBER OF CELLS EVALUATED: approx 5x10 E05

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency

ACTIVATION: S9 mix contained 3% S9 and glucose-6-phosphate and NADP as cofactors.
Evaluation criteria:
A test compound is considered positive in this assay if it causes a statistically significant, dose related increase in mutant frequency at concentrations of test substance resulting in >20% survival, at a level which is significantly above the maximum spontaneous mutant frequency.
Statistics:
t-test

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
>5000 µg/ml
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Remarks on result:
other: strain/cell type: CHO K-1
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Cytotoxicity test: Concentrations in the range of 50-5000 µg/ml were tested for induction of cytotoxicity. There was no effect of the test substance on cloning efficiency of the CHO cells in  the presence or absence of metabolic activation at any concentration  tested.

 

The frequency of mutations was low in all groups.  In the absence of metabolic activation mutant frequencies of test substance treated cells were within the range of historical negative controls (i.e., 0-21 mutants per 10 E06 viable cells. The test substance did not produce significant mutant frequency at any concentration tested in the absence of metabolic activation.  In the presence of metabolic activation, the test substance did induce significant increases of the mutant frequencies at the concentration of 600 µg/ml.  The observed mutant frequencies were within the range of the historical negative control (0- 23 mutants per 10 E+06  viable cells) and did not show a dose response relationship, the statistical significance is the result of normal assay variation rather  than indicative of a mutagenic effect of the test substance.

Table 1 Mutant frequency (x10E-06) (mean of 5 flasks)

Concentration µg/ml

Experiment 1

Experiment 2

- MA

+ MA

cytotoxicity

- MA

+ MA

cytotoxicity

0 *

3

1

no

4

3

no

200

2

1

no

5

3

no

600

2

5***

no

0

8****

no

1800

0

0

no

0

5

no

3000

1

1

no

5

3

no

5000

0

3

no

1

2

no

Positive control

265**

290**

no

342**

230**

no

* Solvent control with culture medium

** Highly significant, no statistical evaluation

*** Statistically significant, P<0.001 but within the range of the historical negative control

**** Statistically significant 0.1<P<0.05

but within the range of the historical negative control


Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with and without activation

3-aminopropyltriethoxysilane has been tested in a reliable assay according to OECD TG 476 and under GLP. Expected results were obtained from medium and positive controls. The results from the repeat experiment were consistent with those from the initial test. No increase in the mutant frequency was observed in Chinese hamster Ovary (CHO) cells in the absence of activation. In the presence of activation, a statistically significant increase was observed at a single concentration. As this result was within the range of the mutant frequencies of the historical negative controls, and no dose response relationship was observed, the increases are a result of normal assay variation rather than a mutagenic effect of the test substance. It is the opinion of the reviewer that although the test substance hydrolyses in water, and so the use of aqueous cell culture medium may have led to exposure of the test organisms to the products of hydrolysis rather than the test substance itself, this does not invalidate the test, as hydrolysis would occur in exposed organisms. It is concluded that the test substance in not mutagenic to mammalian cells under the conditions of the test.