Registration Dossier

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:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Qualifier:
according to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Creosote WEI-Type B
- Name of test material (as cited in study report): Creosote Spéciale 14130
- Molecular formula (if other than submission substance): not applicable, UVCB
- Substance type: organic
- Physical state: liquid
- Composition:

[w/w%]
=========================
Aromatic hydrocarbons 89.7
Phenols 6.8
N-Compounds 3.4
Benzene 0.04
Toluene 0.22
Ethyl-Benzene 0.21
m/p-Xylene 0.70
Styrene 0.12
o-Xylene 0.24
Indane 3.1
Indene 2.9
Naphthalene 12.2
2-Me-Naphthalene 5.3
1-Me-Naphthalene 3.3
Diphenyl 2.7
Acenaphthene 12.6
Fluorene 10.3
Phenanthrene 4.6
Anthracene 1.2
Fluoranthene 0.7
B(a)P 15 ppm
B(a)A 40 ppm
B(b)F 15 ppm
B(h)F + B(j)F 10 ppm
DiB(a, h)A < 5 ppm
Phenol 0.5
o-cresol 1.7
p-cresol 1.4
m-cresol 1.6
Xylenols 1.3
===========================



Test animals

Species:
mouse
Strain:
other: OF1 (IOPS Caw)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Iffa-Crédo, 69592 L´Arbresle France
- Age at study initiation: Young adults, 6 – 8 weeks of age
- Weight at study initiation: 28.4 – 34.2 g (m), 22.8 – 30.3 g (f)
- Assigned to test groups randomly: yes

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Olive oil
Details on exposure:
--
Duration of treatment / exposure:
see below: time points
Frequency of treatment:
single dose
Post exposure period:
Time points of sampling: 24, 48, 72 h after treatment
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 2200 mg/kg bw (limit test)
Basis:
actual ingested
in olive oil (total volume 10 mL/kg bw)
No. of animals per sex per dose:
5 per time point
Control animals:
yes, concurrent vehicle
Positive control(s):
- Cyclophosphamide
- Route of administration: i.p.
- Doses / concentrations: a single application of 100 mg/kg bw

Examinations

Tissues and cell types examined:
Bone marrow
Number of animals: all animals
Number of cells: 1000 per animal
Type of cells erythrocytes in bone marrow
Parameters: numbers and types of structural aberrations
polychromatic/normochromatic erythrocytes ratio
mitotic index
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
Acute toxicity: A preliminary test with 220, 1100, 2200, and 11000 mg/kg creosote and 2 males and 2 females per group preceded the main study.No mortality but clear clinical signs of toxicity at 2200 mg/kg. One hundred per cent mortality within 3 d for all animals at the highest dose.

DETAILS OF SLIDE PREPARATION: May-Grünwald-Giemsa staining

Statistics:
Arithmetic means, Student´s test, indicator of significance p < 0.01

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Remarks:
clinical signs of toxicity
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid

Any other information on results incl. tables

No significant increases of the number of polychromatic erythrocytes bearing micronuclei were observed in treated animals at any time interval. A marked decrease in the ratio of polychromatic to normochromatic erythrocytes was observed after 72-h exposure, indicating a significant cytotoxic treatment-related effect on erythrocytes formation.

The positive control substance produce significant increases in the incidence of micronucleated cells and clear depression in the cellular ratio of poly- to normochromatic erythrocytes.

Table for Micronucleus Test In Vivo (MN)

Positive

control group

Vehicle control

High dose
[2200 mg/kg]

Number of cells evaluated per 10 animals (group)

10,000

10,000/time point

10,000/time point

Sampling time (h)

24

24

48

72

24

48

72

Number of erythrocytes

normochromatic

Not specified

polychromatic

Not specified

polychromatic with micronuclei

male

31.2 ±4.0

0.4 ±0.5

1.2 ±0.8

0.6 ±0.9

0.4 ±0.5

0.4 ±0.5

0.4 ±0.5

female

30.6 ±8.0

1.2 ±1.1

0.2 ±0.4

0.2 ±0.4

0.2 ±0.4

0.4 ±0.9

0.2 ±0.4

Ratio of erythrocytes

polychromatic / normochromatic

Not specified

polychromatic with micronuclei / normochromatic
(males + females combined)

0.57 ±0.13

1.03 ±0.25

0.78 ±0.23

1.00 ±0.16

0.84 ±0.14

0.71 ±0.11

0.62 ±0.07

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Executive summary:

Creosote spéciale WEI Type B [containing less than 50 ppm B(a)P] was tested for its capability to induce clastogenic effects in red blood cells isolated from bone marrow after three time points i.p. post-application. The study was conducted according to OECD guideline 474 (1983) EEC Directive 84/449, B.12 (1984). Based on the results of a preliminary toxicity study, a limit test at 2200 mg/kg (single dose, oral) was carried out. Following treatment with creosote, possibly clastogenic and toxic effects during development of erythroblasts into polychromatic red blood cells were examined at three time intervals after application on 10 animals each (5 m, 5 f). The ratio of polychromatic (immature) to normochromatic (mature) cells was followed as measure of cytotoxicity.

Under the conditions of in-vivo testing, Creosote spéciale 14130, WEI Type B, was negative for the induction of clastogenic/chromosomal defects in developing erythrocytes in vivo, thus showing no mutagenic potential.