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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1985-11-05 to 1987-01-26
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was conducted according to or similar to guideline study OECD TG 473, without exceptions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report Date:
1987

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: oily liquid
Details on test material:
Read across to unrefined and acid treated oils
- Name of test material (as cited in study report): L-06 Light Hydrotreated Feedstock
- Physical state: liquid
- Lot/batch No.: 96524
- Expiration date of the lot/batch: 09/19/90
- Stability under test conditions: not determined by Microbiological Associates, Inc.
- Storage condition of test material: room temperature

Method

Target gene:
ovary
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 rat liver
Test concentrations with justification for top dose:
Dose levels of 0.2, 0.1, 0.05 and 0.02 uL/mL without S-9 activation and 0.03, 0.15, 0.08 and 0.03 uL/mL with S-9 activation were used.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controls
Untreated negative controls:
yes
Remarks:
untreated cells
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
triethylenemelamine
Remarks:
Migrated to IUCLID6: Cyclophosphamide used for S-9 activated study
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)
DURATION
- Preincubation period: 16-24 hours
- Exposure duration: 10 non-activation, two hours for S-9 activated
- Expression time (cells in growth medium): 8 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 10 hours

NUMBER OF CELLS EVALUATED: 100 metaphase cells were examined for each dose level.


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
The number of types of aberrations found was presented for each treatment group. The percentage of damaged cells in the total population of cells examined was calculated for each group. Frequency of structural aberrations per cell was calculated for each group.
Statistics:
Student's t test was used to analyze the frequency of structural aberrations per cell. Chi-square analysis using a 2x2 table was used to ascertain differences between the percentage of cells with numerical aberrations and each treatment group relative to the vehicle control.

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
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:

RANGE-FINDING/SCREENING STUDIES: Dose levels for chromosome aberration assay were selected based on preliminary toxicity tests based on cell survival after treatment relative to the solvent control. CHO Cells were exposed to nine concentrations of test article ranging from 1.0 uL/mL to 0.0001 uL/mL in the presence and absence of an S-9 reaction mixture.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The positive and negative controls fulfilled the requirements for a valid test. Under the conditions of the assay, L-06 did not induce a statistically significant increase in the frequency of structural or numerical aberrations in the CHO cells, in the absence or presence of metabolic activation system.
Executive summary:

Read across justification

No in vitro chromosome aberration tests have been reported for slack waxes (carcinogenic or unknown feed-stock), but such studies have been reported for unrefined / acid treated lubricant base oils, materials similar to the oil entrained in slack waxes (carcinogenic or unknown feed-stock).

In a mammalian cell chromosome aberration study, CHO cell cultures were exposed to L-06 in DMSO at concentrations of 0.2, 0.1, 0.05 and 0.02 µL/mL without S-9 activation and 0.03, 0.15, 0.08 and 0.03 µL/mL with S-9 activation for 10 hours for non-activation and two hours for activation. L-06 was tested up to precipitating concentrations. Positive controls induced the appropriate response. The test material did not demonstrate mutagenciity in the chromosomal aberration assay using Chinese hamster ovary cells.

This study received a Klimisch score of 1 and is classified as reliable without restriction because it was conducted according to or similar to guideline study OECD TG 473.