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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
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: EPA Health Effects Test Guidelines, HG-Gene Muta-Somatic cells, EPA Report No. 560/6-82-001, August 1982
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified

Method

Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
0.1, 0.2, 0.3, 0.4, 0.6 and 0.8 mg/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: methanol;
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: dimethylnitrosamine
Remarks:
with activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 5 hours
- Expression time (cells in growth medium): 2-3 days
- Selection time (if incubation with a selection agent): 9-12 days
- Fixation time (start of exposure up to fixation or harvest of cells):

SELECTION AGENT (mutation assays): TG

NUMBER OF REPLICATIONS: duplicate cultures

NUMBER OF CELLS EVALUATED 2 x 10E5 cells/plate in 5 plates/dosed culture (i.e. 1 x 10E6 total cells/dosed culture).

DETERMINATION OF CYTOTOXICITY
- Method: other: clonal assay; growth inhibition
- Preliminary experiments (0.001 to 10 mg/ml without S9; 0.03 to 3 mg/ml with S9) were performed with CHO cells to determine an appropriate range of test concentrations in which the highest concentration would kill no more than (approximately) 90% of the treated cells both in the presence and absence of a rat-liver S9 metabolic activation system


METABOLIC ACTIVATION: S9 homogenate from Aroclor induced Sprague Dawley rats was purchased from Microbiological Associates or from Litton Bionetics. Concentration of S9 in each study was based on evaluation of relative toxicity and mutant production by the positive control. The S9 mix contained 10 µmoles/ml MgCl, 30 µmoles/ml KCl, 5 µmoles/ml glucose-6-phosphate, 4 µmoles/ml NADP-oxidised, 50 µmoles/ml Na3HPO4, 10 µmoles/ml CaCl2 and 50-200 µl/ml S9. I ml of S9 mix was added to 4.0 ml culture medium.
Evaluation criteria:
A statistically significant, repeatable dose-dependent increase in the mutant frequency is considered to be a positive result.
Statistics:
Student's t-test

Results and discussion

Test results
Key result
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
>1.0 mg/ml
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Preliminary test results with 3-(trimethoxysilyl)propyl methacrylate indicated that concentrations above 1.0 mg/ml were lethal to CHO cells. 

Any other information on results incl. tables

3-(Trimethoxysilyl)propyl methacrylate did not produce any statistically significant increases in the incidence of mutations of CHO cells at concentrations between 0.1 to 0.8 mg/ml in tests with and without an S9 metabolic activation system.  The range of doses tested in this study produced cytotoxic effects which indicated suitable concentrations were evaluated for
mutagenic potential.  The highest dose produced decreases in cell growth assessed 24 hour after exposure.  However, the
colony forming potential was essentially normal for the cells treated without S9 and only moderately depressed for
cells exposed to 
3-(trimethoxysilyl)propyl methacrylate together with S9 activation. Positive, negative and solvent controls produced the expected results.

Table 1 Results without metabolic activation: plating efficiency and (mean of 4 plates)

Concentration

mg/ml

Culture

Plating efficiency

Mutant determination

Mean colonies/plate

% of combined solvent control

Mean colonies per plate

Total colonies

Mutation frequency

0.2

A

115.2

94.7

0

0

0

B

148.0

121.7

0

0

0

0.4

A

133.5

109.8

0

0

0

B

113.8

93.6

0

0

0

0.6

A

120.0

98.7

0

0

0

B

126.0

103.6

0

0

0

0.7

A

137.8

113.3

0.2

1

0.7

B

134.5

110.6

0.6

3

2.2

0.8

A

100.2

82.4

0

0

0

B

114.5

94.2

0.8

4

3.5

Solvent*

A

93.0

76.5

2.0

10

10.8

B

150.2

123.5

0.4

2

1.3

Negative**

136.5

112.3

0

0

0

Positive***

128.5

105.7

27.8

139

108.2

*Solvent control with methanol

** Negative control with cell culture medium

*** Positive control with Ethylmethansulfonate

Table 2 Results with metabolic activation: plating efficiency and (mean of 4 plates)

Concentration

mg/ml

Culture

Plating efficiency

Mutant determination

Mean colonies/plate

% of combined solvent control

Mean colonies per plate

Total colonies

Mutation frequency

0.2

A

102.2

101.7

0.2

1

1.0

B

101.8

101.3

0

0

0

0.3

A

126.5

125.9

0.8

4

3.2

B

112.8

112.2

1.8

9

8.0

0.4

A

116.5

115.9

0

0

0

B

117.5

116.9

1.0

5

4.3

0.6

A

1075

107.0

0.4

2

1.9

B

137.5

136.8

0.6

3

2.2

0.8

A

98.5

98.0

0

0

0

B

120.8

120.2

0.6

3

2.5

Solvent*

A

91.8

91.3

0.8

4

4.4

B

109.2

108.7

0.2

1

0.9

Negative**

117.0

116.4

1.0

5

4.3

Positive***

105.2

104.7

28.8

144

136.8

*Solvent control with methanol

** Negative control with cell culture medium

*** Positive control with dimethylnitrosamine

Applicant's summary and conclusion

Conclusions:
3-(Trimethoxysilyl)propyl methacrylate has been tested for mutagenicity in Chinese hamster ovary cells according to a US EPA method and under GLP. No test-substance induced increase in the number of mutations was observed. Appropriate solvent, negative (cell culture medium) and positive controls were included and gave expected results. It is concluded that 3-trimethyoxysilylpropyl methacrylate is negative for mutagenicity to mammalian cells under the conditions of the test.