Fatty acids, C16-18

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance CAS 112-85-6. In accordance to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals

Deviations:

no

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Docosanoic acid

EC Number:

204-010-8

EC Name:

Docosanoic acid

Cas Number:

112-85-6

Molecular formula:

C22H44O2

IUPAC Name:

docosanoic acid

Method

Target gene:

not applicable

Species / strain

Species / strain / cell type:

mammalian cell line, other: Chinese hamster lung (CHL) cells

Details on mammalian cell type (if applicable):

- Type and identity of media: Eagle-MEM liquid medium
- Properly maintained: yes

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 from rat liver, induced with phenobarbital and 5,6-benzoflavone

Test concentrations with justification for top dose:

-S9 mix (short-term exposure): 0, 875, 1750, 3500 µg/mL
+S9 mix (short-term exposure): 0, 875, 1750, 3500 µg/mL
-S9 mix (24-hour continuous exposure): 0, 350, 700, 1400, 2800 µg/mL
-S9 mix (48-hour continuous exposure): 0, 288, 575, 1150, 2300 µg/mL

Vehicle / solvent:

1.0 % Carboxymethylcellulose sodium

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: continuous exposure: Mitomycin C (0.05 µg/mL for 24 hours and 0.025 µg/mL for 48 hours); short-term exposure, Cyclophosphamide (12.5 µg/mL)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 3 days
- Exposure duration: 6 (short-term exposure), 24, 48 hours

STAIN (for cytogenetic assays): Giemsa

NUMBER OF CELLS EVALUATED: 200

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

The frequency of polyploid cells or cells with abnormal structure of each test group were determined according to the criteria of Ishidate.

Results and discussion

Test results

Species / strain:

mammalian cell line, other: Chinese hamster lung (CHL) cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Water solubility: insoluble in water, soluble in alcohol, ether, chloroform and acetone
- Precipitation: observed on the slide of continuous exposure high dose group

RANGE-FINDING/SCREENING STUDIES: see 'Any other information on material and method incl. tables'

COMPARISON WITH HISTORICAL CONTROL DATA: this test was valid, since the frequency of chromosomal aberration in positive control was within background data.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Results of growth inhibition test

Test item	Concentration in µg/mL	Survival in %
Exposure period 24 h, without S9 mix
1% CMC▪Na		100
Test substance	272	97.7
	454	95.2
	756	96.5
	1260	83.1
	2100	62.1
	3500	37.8
Exposure period 48 h, without S9 mix
1% CMC▪Na		100
Test substance	272	101.1
	454	104.6
	756	98.9
	1260	89.7
	2100	75.9
	3500	1.3
Exposure period 6 h, without S9 mix
1% CMC▪Na		100
Test substance	272	109.6
	454	93.7
	756	102.5
	1260	110.7
	2100	89.8
	3500	95.1
Exposure period 6 h, with S9 mix
1% CMC▪Na		100
Test substance	272	84.3
	454	85.9
	756	85.3
	1260	86.5
	2100	68.3
	3500	76.3

Table 2: Results of chromosome aberration test

Test item	Concentration	Aberrant cells in %			Polyploid cells in %
	in µg/mL	with gaps	without gaps
Exposure period 24 h, without S9 mix
1% CMC▪Na		0.5	0.5	0.0
MMC	0.05	56.0	52.5	0.5
Test substance	350	1.0	1.0	0.5
	700	1.0	0.5	0.5
	1400	0.5	0.0	0.0
	2800	Toxic
Exposure period 48 h, without S9 mix
1% CMC▪Na		0.0	0.0	0.5
MMC	0.025	58.5	54.5	0.0
Test substance	288	1.0	1.0	0.0
	575	0.5	0.0	0.5
	1150	2.0	1.5	0.0
	2300	Toxic
Exposure period 6 h, without S9 mix
1% CMC▪Na		1.5	0.5	0.5
CP	12.5	0.5	0.0	0.5
Test substance	875	0.5	0.5	0.0
	1750	3.0	2.5	0.0
	3500	1.0	0.5	0.5
Exposure period 6 h, with S9 mix
1% CMC▪Na		1.5	1.0	0.0
CP	12.5	63.5	61.5	0.0
Test substance	875	2.5	1.5	1.0
	1750	2.0	2.0	0.0
	3500	2.0	2.0	0.0

CMC▪Na: carboxymethylcellulose sodium (solvent)

MMC: Mitomycin C; CP: Cyclophosphamide (positive controls)

 

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

The test substance did not induce structural chromosomal aberrations in the absence or presence of an exogenous metabolic activation system.