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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
2 November - 10 November 1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The target chemical belongs to the homologues series of glymes, where there is an incremental increase in the number of CH2CH2O units. Therefore, it can be assumed that target and other glyme members (mono-, di-, and triglyme) share the same toxic mode action.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1982
Report Date:
1982

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
early sample collection
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
colorless clear liquid
Purity: > 99%
- MW 90.12
- LogPow - 0.21
- Vapour pressure (20°C) 6600 Pa
- Water solubility miscible

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
50 NMRI mice (Hoe NMRKf(SPF71, Breeder: Pharma Forschung Toxikologe, Kastengrund, Germany)
Age: 7-12 weeks
Body weight:
- male: 30-38 g (mean: 33 g)
- female: 23-27 g (mean: 25 g)
Housing: groups of five animals in Makrolon type-3 cages with wire mesh tops and softwood bedding
Diet: pelleted Altromin diet 1324 ad libitum
Water: Community tap-water, ad libitum
Room temperature: 22-24°C
Humidity: 41-49%

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
deionised water
Details on exposure:
A pre study revealed that 2000 mg/kg bw/d was the maximum tolerated dose.

Treatment:
Five males and five females were assigned to each test group. Animals were treated orally twice (one application per day) with either three doses of the test substance, the positive control (Cyclophosphamide) or the vehicle control (deinised water). Six hours after the last application the bone marrow of the animals was prepared.

Preparation of the animals:
The animals were killed and the femora were removed, the epiphyses were cut off and the marrow was flushed out with foetal calf serum using a syringe. The cell suspension was centrifuged at 1000 rpm for 5 min and the supernatant was discarded. A small drop of re-suspended cell pellet was spread on a slide. The smear was air-dried and stained with May-Grünwald/Giemsa.

Bone marrow smears were scored microscopically for micronucleated polychrmoatic erythrocytes. To analyse target organ cytotoxicity the ratio between polychrmoatic and normochromatic erythrocytes was determined. 2000 polychromatic erythrocytes per animal were analysed for appearance of micronuclei. The count of micronuclei containing normocytes was determined.
Duration of treatment / exposure:
2 applications (one per day)
Frequency of treatment:
daily
Post exposure period:
6 hours
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
20 mg/kg bw/d
Basis:
actual ingested
Remarks:
Doses / Concentrations:
200 mg/kg bw/d
Basis:
actual ingested
Remarks:
Doses / Concentrations:
2000 mg/kg bw/d
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
Cyclophosphamide 100 mg/kg bw/d

Examinations

Tissues and cell types examined:
Please refer to "Details on exposure"
Details of tissue and slide preparation:
Please refer to "Details on exposure"
Evaluation criteria:
5 animals per group and sex and 2000 polychromatic erythrocytes per animal were evaluated.
Statistics:
Performed by computer programm "Diamant" (Code: SG-PA Nr. 4453) programmed by the Department of Praktische Methamatik of the Hoechst AG, Frankfurt, Germany.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
Please refer to "Remarks on results"

Any other information on results incl. tables

Analogue approach Justification (target chemical: tetraglyme; source chemical: monoglyme):

a.   The target chemical belongs to the homologues series of glymes, where there is an incremental increase in the number of CH2CH2O units. Therefore, it can be assumed that target and other glyme members (mono-, di-, and triglyme) share the same toxic mode action.

b.   The findings in repeated dose toxicity studies are comparable for target and source chemicals: the target is the male reproductive organ. Further, findings in thymus and altered hematological values are indicative of altered blood system.

c.    The findings in reproductive performance are comparable: No live pubs and/or reduced number of pubs were the common finding.

d.   The findings in developmental toxicity studies are comparable: the most notable findings were paw skeletal malformations. These findings were observed also at dose levels not associated with apparent maternal toxicity.

Results ofin vivo Micronucleus Test in NMRI-Mice (males)

 

Dose
[mg/kg bw/d]

Animal
No.

MN1/
2000 PE2

MN1/
1000 NC3

Ratio
PE2/NC3

 

 

 

 

 

Control

1

6

1

751:1000

 

2

9

2

725:1000

 

3

5

3

865:1000

 

4

9

1

839:1000

 

5

8

1

858:1000

20

11

6

1

966:1000

 

12

10

4

748:1000

 

13

7

1

823:1000

 

14

10

3

823:1000

 

15

8

2

607:1000

200

21

5

2

710:1000

 

22

4

4

796:1000

 

23

7

2

791:1000

 

24

7

3

1063:1000

 

25

9

1

663:1000

2000

31

5

2

969:1000

 

32

3

2

1217:1000

 

33

7

4

673:1000

 

34

8

1

767:1000

 

35

14

2

956:1000

Cyclophosphamide

41

154

2

649:1000

 

42

184

3

343:1000

 

43

162

3

489:1000

 

44

165

4

440:1000

 

45

211

4

450:1000

 

 

 

 

 

1          Micronuclei

2          polychromatic erythrocytes

3          NormocytesResults ofin vivoMicronucleus Test in NMRI-Mice (females)

 

Dose
[mg/kg bw/d]

Animal
No.

MN1/
2000 PE2

MN1/
1000 NC3

Ratio
PE2/NC3

 

 

 

 

 

Control

6

4

0

920:1000

 

7

1

1

907:1000

 

8

8

1

1126:1000

 

9

6

2

891:1000

 

10

9

2

1098:1000

20

16

8

5

1054:1000

 

17

5

1

851:1000

 

18

5

3

851:1000

 

19

4

1

986:1000

 

20

6

1

913:1000

200

26

5

1

928:1000

 

27

5

4

1336:1000

 

28

5

0

961:1000

 

29

5

2

838:1000

 

30

10

2

1195:1000

2000

36

8

1

991:1000

 

37

5

2

1350:1000

 

38

9

3

916:1000

 

39

9

4

1223:1000

 

40

10

2

1205:1000

Cyclophosphamide

46

122

2

496:1000

 

47

70

1

563:1000

 

48

148

1

345:1000

 

49

134

2

512:1000

 

50

146

4

446:1000

 

 

 

 

 

1          Micronuclei

2          polychromatic erythrocytes

3          Normocytes

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Based on the analogue approach using monoglyme as read-across supporting substance, tetralyme is not considered to be mutagenic.
Executive summary:

The mutagenicity of tetraglyme was assessed based on the analogue approach using monoglyme as read-across supporting substance.

Animals treated with monoglyme up to 2000 mg/kg bw/d (2 applications, one daily) did not show any clinical sign. All animals survived until the study termination.

The number of micronuclei containing polychromatic erythrocytes and normocytes were not influenced by the treatment with monoglyme. The ratio polychromatic erythrocytes/normocytes did not differ to the ratio obtained from the negative control animals.

Cyclophosphamide (positive control) showed a significant increase of induced mirconucleus frequency.

In conclusion, it can be stated that during the study monoglyme did not induce micronuclei as determined by the micronucleus test in the bone marrow cells of the mouse. Based on the analogue approach using monoglyme as read-across supporting substance, tetralyme is not considered to be mutagenic.