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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Constituent 1
Reference substance name:
stannous sulphate
IUPAC Name:
stannous sulphate

Method

Species / strain
Species / strain / cell type:
mammalian cell line, other: ncultured human peripheral blood lymphocytes
Additional strain / cell type characteristics:
other: female
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
0.2500 - 300 µg/mL (> 40 different doses)
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
without S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
cyclohexylamine
Remarks:
with S9

Results and discussion

Test resultsopen allclose all
Species / strain:
mammalian cell line, other: cultured human peripheral blood lymphocytes
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
mammalian cell line, other: cultured human peripheral blood lymphocytes
Metabolic activation:
without
Genotoxicity:
ambiguous
Remarks:
negative for 3+17hr; positive for 20+0 hr
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Stannous Sulfate, crystalline was tested in an in vitro cytogenetics assay using duplicate human lymphocyte cultures prepared from the pooled blood of three female donors in two independent experiments. Treatments covering a broad range of concentrations, separated by narrow intervals, were performed both in the absence and presence of metabolic activation (S-9) from Aroclor 1254 induced animals. The test article was formulated in water for irrigation (purified water). The highest concentrations used in the Main Experiments were limited by toxicity and were determined following preliminary cytotoxicity Range-Finder Experiments. Treatments were conducted (as detailed in the following summary tables) 48 hours following mitogen stimulation by phytohaemagglutinin (PHA). The test article concentrations for chromosome analysis were selected by evaluating the effect of Stannous Sulfate, crystalline on mitotic index. In each experiment, chromosome aberrations were analysed at three or four concentrations.

Appropriate negative (vehicle) control cultures were included in the test system in both experiments under each treatment condition. The proportion of cells with structural aberrations (excluding gaps) in these cultures fell within current historical vehicle control (normal) ranges. 4-Nitroquinoline 1-oxide (NQO) and cyclophosphamide (CPA) were employed as positive control chemicals in the absence and presence of rat liver S-9 respectively. Cells receiving these were sampled in each experiment, 20 hours after the start of treatment; both compounds induced statistically significant increases in the proportion of cells with structural aberrations. All acceptance criteria were considered met and the study was accepted as valid. Treatment of cells with Stannous Sulfate, crystalline for 3+17 hours in the absence of S-9 in Experiment 1 resulted in frequencies of cells with structural aberrations that were generally similar to those observed in concurrent vehicle control cultures. Numbers of aberrant cells (excluding gaps) fell within the 95th percentile of the observed range (0-3% aberrant cells) with the exception of one culture at the highest concentration analysed (5.000 μg/mL) in which 6% aberrant cells were observed, which fell outside the observed range of 0-4%. Treatment of cells for 20+0 hours in the absence of S-9 in Experiment 2 resulted in frequencies of cells with structural aberrations that were significantly higher (p ≤ 0.01) than those observed in concurrent vehicle control cultures at the highest two concentrations analysed (4.500 and 5.000 μg/mL, giving 42% and 57% mitotic inhibition, respectively). Numbers of aberrant cells (excluding gaps) exceeded the 95th percentile of the observed range in both cultures at 5.000 μg/mL and in single cultures at 4.000 and 4.500 μg/mL. The Experiment 2 data fulfilled the criteria for a positive result. Treatment of cells for 3+17 hours in the presence of S-9 in Experiment 1 resulted in frequencies of cells with structural aberrations that were slightly elevated, compared to those observed in concurrent vehicle control cultures, at all concentrations analysed. Numbers of aberrant cells (excluding gaps) exceeded the 95th percentile of the observed range (0-3% aberrant cells) in single cultures at all three concentrations analysed (7%, 6% and 5% at 80.00, 130.0 and 200.0 μg/mL, respectively). The aberrant cell frequencies (excluding gaps) in the replicate cultures at all three concentrations fell within the 95th percentile of the observed range, but the mean aberration frequencies exceeded the 95th percentile of the observed range at 80.00 and 200.0 μg/mL. These data were considered equivocal when viewed in isolation. Treatment of cells for 3+17 hours in the presence of S-9 in Experiment 2 resulted in frequencies of cells with structural aberrations that were significantly higher (p ≤ 0.001) than those observed in concurrent vehicle control cultures at the highest three concentrations analysed (100.0, 140.0 and 160.0 μg/mL, giving 39%, 53% and 57% mitotic inhibition, respectively). Numbers of aberrant cells (excluding gaps) exceeded the 95th percentile of the observed range in both cultures analysed at these concentrations. The Experiment 2 data fulfilled the criteria for a positive result, thus substantiating the result observed in Experiment 1 under this treatment condition. No increases in the frequency of cells with numerical aberrations, which exceeded the concurrent controls and the normal ranges, were observed in cultures treated with Stannous Sulfate, crystalline in the absence and presence of S-9 in Experiments 1 and 2. It is concluded that Stannous Sulfate, crystalline induced structural chromosome aberrations in cultured human lymphocyte cells when tested for 3+17 hours in the presence of S-9 and for 20+0 hours in the absence of S-9. In the same test system, Stannous Sulfate, crystalline did not induce structural chromosome aberrations when tested up to toxic concentrations for 3+17 hours in the absence of S-9..

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive with metabolic activation
ambiguous without metabolic activation negative for 3+17hr; positive for 20+0 hr

It is concluded that Stannous Sulfate, crystalline induced structural chromosome aberrations in cultured human lymphocyte cells when tested for 3+17 hours in the presence of S-9 and for 20+0 hours in the absence of S-9. In the same test system, Stannous Sulfate, crystalline did not induce structural chromosome aberrations when tested up to toxic concentrations for 3+17 hours in the absence of S-9.