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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:
supporting study
Study period:
no data available
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Reliable with restrictions, as purity and identity of the test item are missing and as the experimental procedure is poorly described. Due to reporting deficiencies this reference will only be used as supportive information.

Data source

Reference
Reference Type:
publication
Title:
Micronucleus induction by chromium and selenium, and suppression by metallothionein inducer.
Author:
Itoh S, Shimada H.
Year:
1996
Bibliographic source:
Mutat. Res. 367, 233-236

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The clastogenic effect of selenium compounds in mouse bone marrow cells has been investigated.
GLP compliance:
no
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Selenious acid
EC Number:
231-974-7
EC Name:
Selenious acid
Cas Number:
7783-00-8
Molecular formula:
H2O3Se
IUPAC Name:
selenous acid
Details on test material:
- Name of test material (as cited in study report): Selenious acid
- Molecular formula (if other than submission substance): H2SeO3
- Physical state: solid
No further details are given.

Test animals

Species:
mouse
Strain:
other: Slc:ddY
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Japan SLC Inc. (Hamamatsu, Shizuoka)
- Age at study initiation: 8-week old
- Housing: 5 mice per metal cage
- Diet: ad libitum
- Water: ad libitum

No further details are given.

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used:physiological saline
No further details.
Details on exposure:
No further details are given.
Duration of treatment / exposure:
for 2 consecutive days
Frequency of treatment:
once a day
Post exposure period:
24 hours
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0.625 mg/kg
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
1.25 mg/kg
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
2.5 mg/kg
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
5 mg/kg
Basis:
nominal conc.
No. of animals per sex per dose:
5 mice per treatment group
Control animals:
yes, concurrent vehicle
Positive control(s):
mitomycin C
- Doses / concentrations: 0.5 mg/kg

Examinations

Tissues and cell types examined:
bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: The dose levels were determined on the basis of preliminary dose finding tests for maximum survival dose.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Animals were killed by cervical dislocation at 24 hours after the second administration and the bone marrow was flushed into a tube containing foetal bovine serum.

DETAILS OF SLIDE PREPARATION: Bone marrow smears were prepared and stained with acridine orange.

METHOD OF ANALYSIS: For each animal, 1000 polychromatic erythrocytes (PCE) were scored for micronuclei (MN) and the frequency of micronucleated polychromatic erythrocytes (MNPCE) was expressed as percent of PCE. A number of PCE in 1000 total erythrocytes (PCE plus normochromatic erythrocytes) were also recorded.
Evaluation criteria:
no data
Statistics:
The Kastenbaum and Bowman method (1970) was used for statistical analysis of MNPCE.

Results and discussion

Test results
Sex:
male
Genotoxicity:
positive
Remarks:
H2SeO3 induced a significant increase in MN-PCE at the highest dose.
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
No further details are given.

Any other information on results incl. tables

Induction of MNPCE by H2SeO3

 Compound Dose (mg/kg)  MNPCE (%)  range  PCE (%)  range
Control**   0.14 +/- 0.05  0 -0.3  58.3 +/- 2.9  49.1 -77.9
 H2SeO3  0.625  0.14 +/- 0.07 0 -0.3   61.8 +/- 2.3  57 -70.4
   1.25  0.20 +/- 0.05  0.1 -0.4  53.7 +/- 2.7  45.6 -58.7
   2.5  0.30 +/- 0.08  0.2 -0.6  61.0 +/- 3.0  51.8 -67.6
   5.0  2.50 +/- 0.61*  1.0 -4.1 45.2 +/- 3.3   35.8 -55.0
 mitomycin C  0.5  2.27 +/- 0.15*  1.0 -3.8  58.7 +/- 1.1  46.5 -65.9

 * Significant difference from current control (p<0.01)

** Sum of 4 experiments

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: Increase in micronucleated cells only at very high, nearly lethal dose, questionable biological relevance. Should only be used as supportive information.
A significant increase in micronucleated cells was observed, with a clear positive finding in the maximum dose of 5 mg/kg. All lower dose levels were in the range of the control (0.0-0.3% MNPCE). However, the dose selection was not clearly justified and a description of the toxic effects is lacking. As stated below one might speculate that the maximum dose already showed signs of near-lethal toxicity, making this positive finding of questionable biological significance.

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