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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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report date:
2013

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
3-(trimethoxysilyl)propyl (2E,4E)-hexa-2,4-dienoate
EC Number:
642-902-2
Cas Number:
163802-53-7
Molecular formula:
C12H22O5Si
IUPAC Name:
3-(trimethoxysilyl)propyl (2E,4E)-hexa-2,4-dienoate
Constituent 2
Reference substance name:
3-(trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate
IUPAC Name:
3-(trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate
Constituent 3
Reference substance name:
2,4-Hexadienoic acid, 3-(trimethoxysilyl)propyl ester, (2E,4E)-
IUPAC Name:
2,4-Hexadienoic acid, 3-(trimethoxysilyl)propyl ester, (2E,4E)-
Test material form:
liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Harlan, Frederick, MD
- Age at study initiation: 7 weeks
- Weight at study initiation: males: 171.3-174.5 g; females: 140.8-143.3 g
- Assigned to test groups randomly: yes
- Fasting period before study: no
- Housing: Micro-Barrier cage
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 1 °C
- Humidity (%): 50 ± 20%
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: none given in study report
- Concentration of test material in vehicle: 100, 200 and 400 mg/ml
- Amount of vehicle (if gavage or dermal): 5 ml
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Dosing solutions were prepared on the day prior to the study. Test material and vehicle where vortexed and stirred until homogenous.
Duration of treatment / exposure:
Twenty four and forty eight hours
Frequency of treatment:
Single dose
Post exposure period:
Twenty four and forty eight hours
Doses / concentrations
Remarks:
Doses / Concentrations:
500, 1000, 2000 mg/kg bw
Basis:
nominal conc.
No. of animals per sex per dose:
Five rats per sex at each dose level (24 h sampling time), five rats per sex at high dose (48 h sampling time).
Control animals:
yes, concurrent vehicle
Positive control(s):
- Positive control substance: cyclophosphamide
- Justification for choice of positive control(s): none given in study report
- Route of administration: oral (gavage)
- Doses / concentrations: 40 mg/kg bw

Examinations

Tissues and cell types examined:
Bone marrow: polychromatic erythrocytes and normochromatic erythrocytes
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: based on toxicity information and guideline recommended high dose

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Sampling times: 24 and 48 hours after dosing

DETAILS OF SLIDE PREPARATION: suspensions of bone marrow cells were spread on a clean glass slides and air dried then fixed in methanol. Two slides were prepared from each rat. One set of slides was stained with acridine orange and used in microscopic evaluation. The second set of slides was frozen

METHOD OF ANALYSIS: Bone marrow was evaluated by fluorescent microscopy. The initial scoring was deemed invalid because of out-of-range historical control values for the vehicle. The slides were therefore re-scored and this data was presented in the study report. Cells were scored under high power. At least 2000 polychromatic erythrocytes (PCE) were scored per animal for micronuclei: the number of cells with micronuclei was recorded. In addition, at least 1000 total erythrocytes (PCEs plus normochromatic erythrocytes (NCE)).

Evaluation criteria:
The test substance is considered positive if it induces a significant increase in micronucleated PCE frequency at any dose level or sampling time compared to the concurrent vehicle control. Other criteria may be used in reaching a conclusion including magnitude of the increase, comparison to historical control values, biological significance.
Statistics:
The frequency of micronucleated PCEs and proportion of PCEs to total erythrocytes was determined for each animal and treatment group. Statistical significance, p ≤ 0.05, was determined using Kastenbaum-Bowman tables.

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
No mortality or clinical signs; no effect on PCE/NCE ratio
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): no induction of micronuclei observed.
- Ratio of PCE/total erythrocytes (for Micronucleus assay): between 0.422 (low dose males) and 0.464 (high dose, 48 h sampling time males).
- Appropriateness of dose levels and route: dose levels and route were appropriate.
- Statistical evaluation: Only the positive control results were statistically significant.

Any other information on results incl. tables

Summary of bone marrow micronucleus assay following single oral administration of test substance

Concentration mg/kg bw

Sex

Time

Number of animals

PCE/Total erythrocytes

Number of mnPCE/1000 PCE

Number of mnPCE/PCE scored

0 (corn oil)

M

24

5

0.479

0.6

6/10000

F

24

5

0.444

0.8

8/10000

500

M

24

5

0.422

0.4

4/10000

F

24

5

0.427

0.6

6/10000

1000

M

24

5

0.427

0.4

4/10000

F

24

5

0.436

0.6

6/10000

2000

M

24

5

0.438

0.5

5/10000

F

24

5

0.436

0.4

4/10000

Cyclophosphamide (40)

M

24

5

0.337

26.0*

260*/10000

F

24

5

0.337

23.6*

236*/10000

Corn oil

M

48

5

0.460

0.8

8/10000

F

48

5

0.457

0.3

3/10000

2000

M

48

5

0.464

0.5

5/10000

F

48

5

0.436

0.5

5/10000

PCE: polychromatic erythrocytes

mnPCE: micronucleated PCE

* statistically significant increase compared to the vehicle control, p≤ 0.05

Applicant's summary and conclusion

Conclusions:
3-(Trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate has been tested in an in vivo micronucleus assay conducted in accordance with OECD 474 and in compliance with GLP. No evidence for systemic toxicity, toxicity to bone marrow or induction of micronuclei was observed at any test concentration in bone marrow sampled 24 hours and 48 hours following oral administration by gavage of a single dose of test substance. The animals were dosed with 500, 1000 and 2000 mg/kg bw (24 h sampling time) and 2000 mg/kg bw (48 hour sampling time), Appropriate positive and vehicle controls were included and gave expected results. It is concluded that the test substance is negative for the induction of micronuclei under the conditions of the test.