Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study not performed to GLP or guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
GLP compliance:
no
Type of assay:
chromosome aberration assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Sodium cyanurate
- Analytical purity: 99.6%
- Lot/batch No.: 1219642-2
- Storage condition of test material: Room temperature

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Simonsen Laboratories, Gilroy, CA
- Weight at study initiation: 160 - 210g
- Diet: ad libitum
- Water: ad libitum



Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle used: 4% carboxymethyl cellulose
- Lot/batch no: Sigma chemical company, Lot 77C-0334
Duration of treatment / exposure:
24 h and 48 h after treatment
Doses / concentrations
Remarks:
Doses / Concentrations:
1.25, 2.50 and 5.00 g/kg bw
Basis:

No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
triethylenemelamine
- Route of administration: Intraperitoneal
- Doses / concentrations:0.275 mg/kg

Examinations

Tissues and cell types examined:
Bone marrow
Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES : 24 and 48 h after treatment


DETAILS OF SLIDE PREPARATION: Clean labeled slides were dipped in distilled water and the cell suspensions were dropped onto the slides using Pasteur pipettes. The slides were then passed over a flame from an alcohol lamp and allowed to dry inside a fume hood. Eight slides were made from each animal. Cells on the slides were stained in freshly prepared 7% Giemsa stain (Gurr R66 Giemsa, M/15 Sorensens buffer, pH 6.8) for 10 minutes at room temperature. The stained slides were rinsed in deionized water, air dried and dipped in xylene, and coverslips were mounted with Depex mounting medium.


METHOD OF ANALYSIS: 50 cells were analyzed from each animal in the study. 1000 cells per animal were examined to determine the mitotic index (MI).For each metaphase cell analyzed for chromosomal aberrations, the vernier setting, chromosome number, and the number and types of aberrations recorded. Aberrations were classified, as described by Savage (1975), as chromosome-type or chromatid-type and were further classified as deletionsor exchanges. Cells bearing ten or more aberrations were classified as 'severely damaged cells'.


Evaluation criteria:
numbers and types of structural aberrations , mitotic index
Statistics:
For each treatment group, data on aberrations per cell was checked for conformity to a Poisson distribution. If the data followed a Poisson distribution, the means for each group were subjected to a square root transformation. If the results did not conform to a Poisson ditribution, a square-root transformation was perfomed on the numbers of chromosomal aberrations per cell and means from each group were calculated from the transformed data. Using the transformed data, the Students t-test was performed to compare the frequency of chromosomal aberrations per cell in a treatment group with that of a negative control. Differences were considered statistically significant when p < 0.05.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative

Any other information on results incl. tables

Table1: Cytogenetic evaluation of bone marrow cells from male rats exposed to sodium cyanurate by oral gavage: 24 hours

Negative control

Low dose (1.25 g/kg)

Mid dose (2.50 g/kg)

High dose (5.0 g/kg)

Positive control (0.275 mg/kg TEM)

No of animals

5

5

5

5

5

Mitotic index (%)

5.28 ± 0.79

5.74 ± 0.71

7.28 ± 0.94

6.49 ± 0.96

4.39 ± 0.60

No of cells analyzed

250

250

238

239

238

No (%) normal cells

231 (92)

231 (92)

224 (94)

227 (95)

159 (67)

Number (%) abnormal cells

19 (8)

19 (8)

14 (6)

12 (5)

79 (33)

Number of gaps per cell (mean ± SEM)

0.05 ± 0.004

0.07 ± 0.008

0.04 ± 0.003

0.03 ± 0.003

0.10 ± 0.008

Number (%) abnormal cells with:

Chromosome deletions

1 (0.4)

1 (0.4)

1 (0.4)

0

8 (3.4)

Chromosome exchanges

0

0

1 (0.4)

1 (0.4)

4 (1.7)

Chromatid deletions

7 (2.8)

8 (3.2)

7 (2.9)

6 (2.5)

50 (21.0)

Chromatid exchanges

8 (3.2)

13 (5.2)

2 (0.8)

5 (2.1)

32 (13.4)

Aneuploidy

4 (1.6)

2 (0.8)

4 (1.7)

1 (0.4)

5 (2.1)

Polyploidy

0

1 (0.4)

1 (0.4)

0

0

Severe damage

0

0

0

0

3 (1.3)

Types of aberrations per cell:

Overall frequency of aberrations (mean ± SEM)

0.08 ± 0.02

0.08 ± 0.02

0.07 ± 0.02

0.05 ± 0.02

0.89 ± 0.12*

Chromosome deletions

0.004

0.004

0.004

0.000

0.040

Chromosome exchanges

0.000

0.000

0.004

0.004

0.020

Chromatid deletions

0.03

0.03

0.03

0.03

0.50

Chromatid exchanges

0.03

0.03

0.01

0.03

0.20

* Significantly different from control, p <0.05

Table 2: Cytogenetic evaluation of bone marrow cells from male rats exposed to sodium cyanurate by oral gavage: 48 hours

Negative control

Low dose (1.25 g/kg)

Mid dose (2.50 g/kg)

High dose (5.0 g/kg)

Positive control (0.275 mg/kg TEM)

No of animals

5

5

5

5

5

Mitotic index (%)

5.25 ± 0.21

5.31 ± 0.18

4.52 ± 0.18

4.37 ± 0.24

5.52 ± 0.24

No of cells analyzed

239

250

250

226

250

No (%) normal cells

224 (94)

229 (92)

224 (90)

210 (93)

110 (44)

Number (%) abnormal cells

15 (6)

21 (8)

26 (10)

16 (7)

140 (56)

Number of gaps per cell (mean ± SEM)

0.06 ± 0.008

0.05 ± 0.005

0.07 ± 0.005

0.04 ± 0.005

0.13 ± 0.009

Number (%) abnormal cells with:

Chromosome deletions

1 (0.40)

0

0

0

9 (3.6)

Chromosome exchanges

1 (0.4)

0

0

0

2 (0.8)

Chromatid deletions

7 (2.9)

11 (4.4)

10 (4)

4 (1.7)

76 (30.4)

Chromatid exchanges

3 (1.3)

7 (2.8)

15 (6)

7 (3)

64 (25.6)

Aneuploidy

3 (1.3)

3 (1)

0

5 (2.2)

10 (4)

Polyploidy

2 (0.8)

3 (1)

1 (0.40)

0

0

Severe damage

0

0

0

0

25 (10)

Types of aberrations per cell:

Overall frequency of aberrations (mean ± SEM)

0.07 ± 0.02

0.11 ± 0.03

0.12 ± 0.03

0.09 ± 0.02

2.36 ± 0.70*

Chromosome deletions

0.004

0

0

0

0.05

Chromosome exchanges

0.004

0

0

0

0.01

Chromatid deletions

0.03

0.06

0.06

0.02

0.95

Chromatid exchanges

0.01

0.03

0.06

0.04

0.45

Within the range finder, no mortality was observed at any dose tested. Mitotic indices ranged from 1.50 to 6.18 percent and showed no compound related effects. A dose of 5 g/kg was considered the MTD. For the definitive cytogenetic study, at the 24 hour sacrifice no mortality was observed at any dose tested. No compound related effects were observed at the doses tested. The positive control showed an approximately ten fold increase in aberrations compared to the untreated controls. At the 48  hour sacrifice no mortality was observed at any dose tested. No compound related effects were observed. The positive control showed approximately thirty fold increase in aberrations compared to the untreated controls.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
No mutagenic effects were observed at 24 or 48 hours post dosing, in the bone marrow cells of male rats dosed orally with 1.25, 2.5, or 5.00 g/kg sodium cyanurate.