Registration Dossier

Toxicological information

Genetic toxicity: in vivo

Currently viewing:

Administrative data

Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted according to internationally accepted testing guidelines, are well documented and scientifically acceptable. Justification for Read Across is detailed in the endpoint summary and in the Category Justification Report attached to the section 13.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1973
Report Date:
1973
Reference Type:
publication
Title:
Testing Mutagenic Properties with the Dominant Lethal Test on the Male Mouse.
Author:
Lorke D. and Machemer L.
Year:
1975
Bibliographic source:
Environmental Quality and Safety, Suppl. Vol. 4, 239-246

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)
GLP compliance:
not specified
Type of assay:
rodent dominant lethal assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: S. Ivanovas GmbH, Kisslegg, Germany.
- Age at study initiation: about 10 weeks.
- Weight at study initiation: mean: male: 30-35 g, female: 25-30 g.
- Housing: singly housed in Makrolon Type I, cages with wire mesh top.
- Diet: ad libitum, Altromin pelleted.
- Water: ad libitum.

ENVIRONMENTAL CONDITIONS
- Temperature: 24 - 26 °C.
- Humidity: about 60 %.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle used: Tragacanth.
Details on exposure:
PREPARATION OF DOSING SOLUTIONS
- Test solution: 20 % solution in demineralized water with 1 % tragacanth (corresponding to a volume of 25 ml/kg body weight).
Duration of treatment / exposure:
Single dosage.
Frequency of treatment:
Once.
Doses / concentrations
Remarks:
Doses / Concentrations:
5000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
20 males and 480 females.
Control animals:
yes, concurrent vehicle
Positive control(s):
Methylmethanesulfonate (MMS) and trimethyl phosphate (TMPO)
- Route of administration: MMS: ip and TMPO: oral - gavage
- Doses / concentrations: MMS = 100 mg/kg and TMPO = 1000 mg/kg

Examinations

Tissues and cell types examined:
Number of fertile matings, implantation, resorption, live foetuses, and corpora lutea.
Statistics:
The χ2-test, the t-test or the distribution-free rank sum test (Wilcoxon) were used to assess the results.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
not examined
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The male mice treated with the test substance showed slightly somnolent after the application for about 3 hours. Then they showed a normal activity again, leaving no evidence of adverse effect of the substance seen.
All treated and untreated males survived to the end of the experiment.

FERTILIZATION
There were no significant differences between the untreated controls and the groups treated with the test substance.
The fertilization rates of the control and the treated group differed in all pairing weeks not significant from each other. The values ​​of the treated group were in all weeks slightly under the control; the effect of a substance can not be concluded, since the fertilization rate in general in line with the standard of the tribe.
The results also showed that TMPO treatment had no effect. MMS, on the other hand, considerably reduced the ability of the male to fertilize the female in the first two weeks of mating.

PRE IMPLANTATION LOSSES
Treatment with the test substance did not cause a biologically significant increase in preimplantation losses. This is also shown by comparing the implantation rates, from which pre-implantation losses can be estimated. Similarly TMPO did not increase pre-implantation losses. MMS, however clearly increased pre-implantation losses during the first week and - as can be seen from the number of implantations per female - even caused pre-implantation losses of embryos during the second and third week of mating.

POST IMPLANTATION LOSSES
The results did not differ significantly from those of the controls for any of the mating weeks. TMPO, however, caused a marked increase in post-implantation losses in the second mating week, and MMS in the first and second weeks. This led to a decrease in the number of live foetuses during these weeks.

DOMINANT LETHAL ASSAY
The test substance did not cause dominant lethal mutations. TMPO was effective in the second mating week. MMS had a marked effect in the first two weeks and it was probably also effective to a lesser extent in the third week.

Any other information on results incl. tables

Fertilization

Number of femals Fertilization rate
Used Per female fertilized
Pairing week Control TS Control TS Control TS
1 60 60 53 49 88.3 81.7
2 60 60 49 45 81.7 75.0
3 60 60 51 48 85.0 80.0
4 60 60 42 40 70.0 66.7
5 60 60 41 37 68.3 61.7
6 60 60 44 37 73.3 61.7
7 60 60 43 35 71.7 58.3
8 60 60 42 32 70.0 53.3

Total

480 480 365 323 76.0 67.3

TS: treated group

Post-implantation loss

Living implants Dead implants
Total Used Total Used
Pairing week Control TS Control TS Control TS Control TS
1 565 537 10.7 11.0 23 35 0.4 0.7
2 485 475 9.9* 10.6 29 25 0.6 0.6
3 579 529 11.4 11.0 20 16 0.4 0.3
4 479 418 11.4 10.5* 18 17 0.4 0.4
5 441 412 10.8 11.1 17 15 0.4 0.4
6 534 425 12.1 11.5 19 14 0.4 0.4
7 491 373 11.4 10.7 17 22 0.4 0.6
8 454 334 10.8 10.4 18 10 0.4 0.3

Total

1028 3503 11.0 10.8 161 154 0.4 0.5

TS: treated group; *: significant difference between control and test group.

Pre-implantation loss

Corpora lutea Implantation* Pre implantation losses
Total Used Total Used Total Used
Pairing week Control TS Control TS Control TS Control TS Control TS Control TS
1 605 582 11.4 11.9 587 570 11.1 11.6 18 12 0.3 0.2
2 544 513 11.1 11.4 511 499 10.4 11.1 33 14 0.7** 0.3
3 608 559 11.9 11.6 598 543 11.7 11.3 10 16 0.2 0.3
4 503 450 12.0 11.2 495 435 11.8 10.9** 8 15 0.2 0.4
5 475 437 11.6 11.8 457 425 11.1 11.5 18 12 0.4 0.3
6 557 446 12.7 12.1 552 438 12.5 11.8 5 8 0.1 0.2
7 517 407 12.0 11.6 505 393 11.7 11.2 12 14 0.3 0.4
8 483 357 11.5 11.2 472 344 11.2 10.8 11 13 0.3 0.4

Total

4292 3751 11.8 11.6 4177 3647 11.4 11.3 115 104 0.3 0.3

TS: treated group; *: since it occursthat aplacentawith 2seedlingsfoundat an implantation site,the number ofimplantationsmay be lessthan the sum oflive and deadimplants. **: significant difference between control and treated group.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
The dominant lethal test investigation did not shown any evidence of mutagenicity caused by the test substance.
Executive summary:

Method

The compound was administered orally in single dose to NMRI mice by gavage at the concentration of 5000 mg/kg. Methylmethanesulfonate (MMS) and trimethyl phosphate (TMPO) were used as positive controls.

Each of the 20 male mice in each group was mated with three untreated females directly after treatment. After insemination (determined by vaginal smear), or after a week, the females were isolated. This procedure was repeated weekly for eight weeks.

On the fourteenth day of gestation the females were sacrificed and the numbers of fertile matings, implantations, resorptions, live foetuses, and corpora lutea were determined.

Results

There were no significant differences between the untreated controls and the groups treated with the test substance. Treatment with the test substance did not cause a biologically significant increase in preimplantation losses and the results did not differ significantly from those of the controls for any of the mating weeks.

The test substance did not cause dominant lethal mutations.