D-Glucopyranose, oligomers, decyl octyl glycosides

Genetic toxicity: in vivo

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 based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study. Reliability changed from "1" to "2" according to ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)."

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

1110615-47-9

IUPAC Name:

1110615-47-9

Details on test material:

- Name of test material (as cited in the study report): trade name
- Physical state: White paste
- Analytical purity: no data
- Lot/Batch number: 94061
- Storage conditions: room temperature in the dark

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Limited, Kent, UK
- Age at study initiation: approx. 5-8 weeks
- Weight at study initiation: 25-30 g
- Housing: In groups of up to seven in solid-floor polypropylene cages
- Diet: Rat and Mouse Expanded Diet No. 1, Special Diets Services Limited, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hour): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 03.02.2000 To: 07.03.2000

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

Distilled water
- oral administration

Duration of treatment / exposure:

n.a.

Frequency of treatment:

single

Post exposure period:

24 h, 48 h (vehicle, high dose group)

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 62.5, 125, 250 mg/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

7 (positive control: 5)

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide (5 mg/mL)
- oral administration

Examinations

Tissues and cell types examined:

Femur bone marrow smears

Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
24 h: 0, 62.5, 125, 250 mg/kg bw, positive control
48 h: 0, 250 mg/kg bw

DETAILS OF SLIDE PREPARATION:
Immediately following sacrifice (ie. 24 or 48 h following dosing), both femurs were dissected from each animal, aspirated with foetal calf serum and bone marrow smears prepared following centrifugation and re-suspension. The smears were air-dried, fixed in absolute methanol and stained in May-Grünwald/Giemsa, allowed to air-dry and coverslipped using mounting medium.

METHOD OF ANALYSIS:
Stained bone marrow smears were coded and examined blind using light microscopy at x 1000 magnification. The incidence of micronucleated cells per 2000 polychromatic erythrocytes (PCE-blue stained immature cells) per animal was scored. Micronuclei are normally circular in shape, although occasionally they may be oval or half-moon shaped, and have a sharp contour with even staining. In addition, the number of normochromatic erythrocytes (NCE-pink stained mature cells) associated with 1000 erythrocytes was counted; these cells were also scored for incidence of micronuclei.
The ratio of polychromatic to normochromatic erythrocytes was calculated together with appropriate group mean values and standard deviations.

Evaluation criteria:

A comparison was made between the number of micronucleated polychromatic erythrocytes occurring in each of the test material groups and the number occurring in the corresponding vehicle control group.
A positive mutagenic response was demonstrated when a biologically relevant statistically significant, dose-related increase in the number of micronucleated polychromatic erythrocytes was observed for either the 24 or 48-hour time points, when compared to their corresponding control group.
If these criteria were not demonstrated, then the test material was considered to be non-genotoxic under the conditions of the test.
A positive response for bone marrow toxicity was demonstrated when the dose group mean polychromatic to normochromatic ratio was shown to be statistically significantly lower than the concurrent vehicle control group.

Statistics:

All data were statistically analysed using appropriate statistical methods as recommended by the UKEMS Sub-committee on Guidelines for Mutagenicity Testing Report, Part III (1989). The data was analysed following a transformation using Student's t-test (two tailed) and any significant results were confirmed using the one way analysis of variance.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

see additonal information

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 250, 500, 1000, 2000 mg/kg bw
- Clinical signs of toxicity in test animals:
In animals dosed with the test material via the intraperitoneal route premature deaths occurred at and above 500 mg/kg, and clinical signs were observed at and above 250 mg/kg (increasing in severity with increased dose) as follows:
hunched posture, lethargy, pilo-erection, decreased respiratory rate, ptosis, ataxia, splayed gait, prostration, laboured respiration and pallor of the extremities.
- Sacrifice time: 48 h

RESULTS OF DEFINITIVE STUDY
- Clinical signs:
There were two premature deaths seen in the 48 h 250 mg/kg test material dose group. Clinical signs were observed in animals dosed with the test material at 250 mg/kg in both the 24 and 48 h groups, these included as follows: hunched posture, lethargy, pilo-erection, decreased respiratory rate, ptosis and ataxia. It was considered that the loss of animals due to premature death did not affect the integrity of the study, because at least five analysable animals were available in each group, as recommended in the OECD test guideline.

- Induction of micronuclei / Ratio of PCE/NCE
There was a statistically significant decrease in the PCE/NCE ratio of the 24 h 250 mg/kg test material group when compared to the concurrent vehicle control group. The response was part of a dose-related reduction in PCE/NCE ratios and was taken to indicate that cytotoxicity and exposure of the bone marrow had been achieved.
There was a small, statistically significant, increase in the frequency of micronucleated PCEs in the 24 h 125 mg/kg test material dose group when compared to its control group. However, the response was within the current historical range for vehicle controls, the 24 h vehicle control PCE+MN value was very low and no individual animal values for micronucleated PCEs were greater than would be considered acceptable for vehicle control animals. Therefore, the response was considered to be of no biobogical relevance.
The positive control group showed a marked increase in the incidence of micronucleated polychromatic erythrocytes hence confirming the sensitivity of the system to the known mutagenic activity of cyclophosphamide under the conditions of the test.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative