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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 based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
15-Jun-2001 to 18-Sep-2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was conducted according to a test protocol that is comparable 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:
2001
Report Date:
2001

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Qualifier:
according to
Guideline:
other: Japanese Guidelines on Industrial Chemicals
GLP compliance:
yes
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent

Method

Target gene:
not applicable
Species / strain
Species / strain / cell type:
mammalian cell line, other: CHL/IU (originally derived from female Chinese hamster lung)
Details on mammalian cell type (if applicable):
- Type and identity of media: Eagle's minimum essential medium
- Properly maintained: no data
- Periodically checked for Mycoplasma contamination: no data
- Periodically checked for karyotype stability: no data
- Periodically "cleansed" against high spontaneous background: no data
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
phenobarbital- and 5,6-benzoflavone-induced male rat liver S9
Test concentrations with justification for top dose:
625-5000 µg mixed sodium salts/ml (pulse treatment)
150-3000 µg mixed sodium salts/ml (24-hour continuous treatment)
50-400 µg mixed sodium salts/ml (48-hour continuous treatment)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: saline
- Justification for choice of solvent/vehicle: solubility of test substance in water
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
without S9, 0.1 µg/ml (pulse treatment), 0.03 µg/ml (continuous treatment)
Positive control substance:
mitomycin C
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
with S9, 15 µg/ml (pulse treatment)
Positive control substance:
benzo(a)pyrene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: pulse treatment 6 hours; continuous treatment, 24 or 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells): pulse treatment 24 hours; continuous treatment 24 or 48 hours

SPINDLE INHIBITOR (cytogenetic assays): colcemid, 0.1 µg/ml, 2 hours
STAIN (for cytogenetic assays): Giemsa

NUMBER OF REPLICATIONS: duplicate cultures

NUMBER OF CELLS EVALUATED: 100 cells /culture, 2 cultures/treatment

DETERMINATION OF CYTOTOXICITY
- Method: other: cell density after crystal violet staining

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Determination of endoreplication: yes
- Other: mitotic index
Evaluation criteria:
Negative: both the incidence of aberrant cells (excluding gaps) and that of numerical aberrations <5%
Inconclusive: either of these incidences is 5-10%
Positive: either of these incidences >10%
Statistics:
None

Results and discussion

Test resultsopen allclose all
Species / strain:
mammalian cell line, other: CHL/IU
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
pulse treatment ( 6 and 24 hour exposure)
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
≥ 2500 µg mixed sodium salts/ml (pulse treatment),
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
mammalian cell line, other: CHL/IU
Genotoxicity:
positive
Remarks:
48 hour treatment
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
≥50 µg mixed sodium salts/ml (48-hour continuous treatment)
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no data
- Effects of osmolality: no data
- Evaporation from medium: no data
- Water solubility: soluble in water
- Precipitation: no precipitation observed
- Other confounding effects: no data

RANGE-FINDING/SCREENING STUDIES:
- No, but cell survival was evaluated at 156-5000 µg mixed sodium salts/ml (pulse treatment, 24-hour continuous treatment and 48-hour continuous treatment) and the data used to determine the concentrations that were to be evaluated for chromosome aberrations

COMPARISON WITH HISTORICAL CONTROL DATA: no data

ADDITIONAL INFORMATION ON CYTOTOXICITY: Cell survival:
- Pulse treatment -S9, µg mixed sodium salts/ml: 156 (109%), 313 (109%), 625 (97%), 1250 (96%), 2500 (76%), 5000 (58%)
- Pulse treatment +S9, µg mixed sodium salts/ml: 156 (98%), 313 (104%), 625 (103%), 1250 (108%), 2500 (102%), 5000 (77%)
- 24-hour continuous treatment -S9, µg mixed sodium salts/ml: 156 (115%), 313 (81%), 625 (47%), 1250 (37%), 2500 (19%), 5000 (0%)
- 48-hour continuous treatment -S9, µg mixed sodium salts/ml: 156 (50%), 313 (25%), 625 (7%), 1250 (5%), 2500 (1%), 5000 (0%)
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Full details of the results from the 48 hours treatment (result reported as positive) are not presented in the study report. A graph of the results indicates that the incidence of cells with structural aberrations was 2.5% at 50 µg/ml; 5% at 100; 15% at 150; 37% at 200 and 49% at 300 µg/ml.

Table 1 Chromosome aberration test - treatment time 6 hours

Concentration µg/ml

+/- S9 mix

No. of cells analyzed

Chromatid breaks

Chromatid exchanges

No. of cells with aberrations (%)

No. of cells with gaps

Cell growth index (%)

Polyploid cells

Control

-

200

0

0

0

1

100

0

625

-

200

1

0

1

0

98

0

1250

-

200

3

1

4

0

91

0

2500

-

200

6

1

7

4

71

2

5000

-

200

9

1

9

3

41

0

Positive control

-

200

54

121

139

1

-

0

Control

+

200

0

0

1

0

100

0

625

+

200

0

2

2

1

91

0

1250

+

200

0

1

1

0

95

0

2500

+

200

3

3

4

0

99

0

5000

+

200

1

0

1

0

67

0

Positive control

+

200

7

42

46

1

-

0

 

Chromosome aberration test - treatment time 24 hours

Concentration µg/ml

+/- S9 mix

No. of cells analyzed

Chromatid breaks

Chromatid exchanges

No. of cells with aberrations (%)

No. of cells with gaps

Cell growth index (%)

Polyploid cells

Control

-

200

2

0

2

1

100

0

4.7

-

200

1

1

2

1

101

0

9.4

-

200

2

0

2

0

102

0

18.8

-

200

4

0

4

1

104

0

37.5

-

200

3

2

5

0

107

0

75

-

200

2

1

3

3

103

0

150

-

200

8

0

8

2

113

0

300

-

-

TOXIC

Positive control

-

200

30

30

58

0

-

0

Control

+

200

2

0

2

0

100

0

50

+

200

4

1

5

0

99

0

100

+

200

7

4

11

2

68

0

150

+

200

31

9

34

0

57

0

200

+

200

67

9

74

1

43

0

300

+

200

87

10

97

2

20

0

400

+

-

TOXIC

Positive control

+

200

47

56

86

0

-

0

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive

DTPMP-xNa has been tested in a reliable study, conducted according a protocol that is equivalent to OECD guideline 473 and under GLP. A dose related increase in the number of cells with aberrations was observed after 48 hours treatment in an in vitro chromosome aberration assay. It is concluded that the substance is positive for induction of chromosome aberrations in Chinese hamster lung cells under the conditions of the test.