2,2'-oxydiethanol

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

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:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-oxydiethanol

EC Number:

203-872-2

EC Name:

2,2'-oxydiethanol

Cas Number:

111-46-6

Molecular formula:

C4H10O3

IUPAC Name:

2-(2-hydroxyethoxy)ethan-1-ol

Specific details on test material used for the study:

Purity: 99.932 area %

Test animals

Species:

mouse

Strain:

NMRI

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 26.9 g
- Housing: individual housing in appropriately labeled cages, Makrolon cages, type M I
- Bedding: Type Lignocel FS 14 fibres, dustfree bedding, supplied by SSNIFF, Soest, Germany
- Diet: standardized pelleted feed (Maus/Ratte Haltung "GLP", Provimi Kliba SA, Kaiseraugst, Switzerland), ad libitum
- Water: drinking water from bottles, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24°C
- Humidity (%): 30 - 70%
- Air changes (per hr): fully air-conditioned rooms with central air conditioning
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

purified water

Details on exposure:

The substance to be administered per kg body weight was dissolved in purified water. To achieve a solution of the test substance in the vehicle, the test substance preparation was shaken thoroughly. All test substance formulations were prepared immediately before administration.

Duration of treatment / exposure:

once intraperitoneally

Frequency of treatment:

once intraperitoneally

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

500 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

2 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

vincristine sulfate

Examinations

Tissues and cell types examined:

Bone marrow cells

Details of tissue and slide preparation:

The animals were sacrificed and the bone marrow of the two femora was prepared 24 and 48 hours after administration from the animals of the highest dose group of 2000 mg/kg bw and those of the vehicle control group. In the test groups of 1000 mg/kg and 500 mg/kg bw and in the positive control groups, the 24-hour sacrifice interval was investigated only. After staining of the preparations, 2000 polychromatic erythrocytes were evaluated per animal and investigated for micronuclei. The normocytes with and without micronuclei occurring per 2000 polychromatic erythrocytes were also recorded.
As vehicle control, male mice were administered merely the vehicle purified water by the same route and in the same volume as the animals of the dose groups, which gave frequencies of micronucleated polychromatic erythrocytes within the historical vehicle control data range.

Evaluation criteria:

A finding is considered positive if the following criteria are met:
• Statistically significant and dose-related increase in the number of PCEs containing micronuclei.
• The number of PCEs containing micronuclei has to exceed both the concurrent vehicle control value and the range of the historical vehicle control data.
A test substance is considered negative if the following criteria are met:
• The number of cells containing micronuclei in the dose groups is not statistically significant increased above the concurrent vehicle control value and is within the range of the historical vehicle control data.

Statistics:

The statistical evaluation of the data was carried out using the program system MUKERN (BASF SE). The asymptotic U test according to MANN-WHITNEY (modified rank test according to WILCOXON) was carried out to clarify the question whether there are statistically significant differences between the untreated control group and the treated dose groups with regard to the micronucleus rate in polychromatic erythrocytes. The relative frequencies of cells containing micronuclei of each animal were used as a criterion for the rank determination for the U test. Statistical significances were identified as follows: * p ≤ 0.05 ** p ≤ 0.01. However, both biological relevance and statistical significance were considered together.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Both positive control substances, cyclophosphamide for clastogenicity and vincristine sulfate for spindle poison effects, led to the expected increase in the rate of polychromatic erythrocytes containing small or large micronuclei.
A slight inhibition of erythropoiesis determined from the ratio of polychromatic to normochromatic erythrocytes was detected at 2 000 mg/kg body weight at 48-hour sacrifice interval.
According to the results of the present study, the single intraperitoneal administration of Diethylene glycol did not lead to a relevant increase in the number of polychromatic erythrocytes containing either small or large micronuclei. The rate of micronuclei was close to the range of the concurrent vehicle control in all dose groups and at all sacrifice intervals and within the range of the historical vehicle control data.

Any other information on results incl. tables

Summary table - Induction of Micronuclei in bone marrow cells - single intraperitoneal administration

Test group	Sacrifice	Animal	Micronuclei in PCE		Number
	interval [hrs]	No.	total^a [‰]	large MN^b [‰]	of NCE^c
Vehicle control purified water	24	5	1.3	0.0	3 820
Test substance 500 mg/kg bw.	24	5	0.6	0.0	4 389
Test substance 1 000 mg/kg bw.	24	5	0.6	0.0	4 227
Test substance 2 000 mg/kg bw.	24	5	0.6	0.0	3 941
Positive control cyclophosphamide 20 mg/kg bw.	24	5	20.8**	0.1	6 045
Positive control vincristine sulfate 0.15 mg/kg bw.	24	5	54.3**	17.1**	5 979
Vehicle control purified water	48	5	0.9	0.1	3 138
Test substance 2 000 mg/kg bw.	48	5	1.9	0.0	5 331

PCE	= polychromatic erythrocytes
NCE	= normochromatic erythrocytes
bw.	= body weight
^a	= sum of small and large micronuclei
^b	= large micronuclei (indication for spindle poison effect)
^c	= number of NCEs observed when scoring 10 000 PCEs    (indication for target organ toxicity)
*	= p ≤ 0.05
**	= p ≤ 0.01

Applicant's summary and conclusion

Conclusions:

Under the experimental conditions chosen here, the test substance has no chromosome-damaging (clastogenic) effect nor does it lead to any impairment of chromosome distribution in the course of mitosis (aneugenic activity) in bone marrow cells of NMRI mice in vivo.

Executive summary:

The test substance was assessed for its potential to induce chromosomal damage (clastogenicity) or spindle poison effects (aneugenic activitiy) in NMRI mice using the micronucleus test method. For this purpose, the test substance, dissolved in purified water, was administered once intraperitoneally to male animals at dose levels of 500 mg/kg, 1000 mg/kg and 2000 mg/kg body weight in a volume of 10 mL/kg body weight in each case.

The animals were sacrificed and the bone marrow of the two fermora was prepared 24 and 48 hours after administration in the highest dose group of 2000 mg/kg body weight and in the vehicle controls. In the test groups of 1000 mg/kg and 500 mg/kg body weight and in the positive control groups, the 24 -hour sacrifice interval was investigated only. After staining of the preparations, 2000 polychromatic erythrocytes were evaluated per animal and investigated for micronuclei. The normocytes with and without micronuclei occuring per 2000 polychromatic erythrocytes were also recorded.

As vehicle control, male mice were administered merely the vehicle purified water by the same route and in the same volume as the animals of the dose groups, which gave frequencies of micronucleated polychromatic erythrocytes within the historical vehicle control data range.

Both positive control substances, cyclophosphamide for clastogenicity and vincristine sulfate for spindle poison effects, led to the expected increase in the rate of polychromatic erythrocytes containing small or large micronuclei.

A slight inhibition of erythropoiesis determined from the ratio of polychromatic to normochromatic erythrocytes was detected at 2000 mg/kg body weight at 48 -hour sacrifice interval.

According to the results of the present study, the single intraperitoneal administration of the test substance did not lead to a relevant increase in the number of polychromatic erythrocytes containing either small or large micronuclei.

The rate of micronuclei was close to the range of the concurrent vehicle control in all dose groups and at all sacrifice intervals and within the range of the historical vehicle control data.

Thus, under the experimental conditions of this study, the test substance does not induce cytogenetic damage in bone marrow cells of NMRI mice in vivo.