Barium hydroxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline conform study with GLP.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

barium(2+) dichloride dihydrate

EC Number:

600-412-6

Cas Number:

10326-27-9

IUPAC Name:

barium(2+) dichloride dihydrate

Details on test material:

- Name of test material (as cited in study report): barium chloride dihydrate
- EC number: 233-788-1
- Substance type: pure active substance
- Physical state: a whcitrey stalline granule or powder

Method

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

no data available

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

Trial 1, without S9: 50, 160, 500 and 1600 µg/mL
Trial 1, with S9: 50, 160, 500, 1600 and 5000 µg/mL
Trial 2, without S9: 100, 250, 500, 1000, 1500 and 2000 µg/mL
Trial 2, with S9: 500, 1600, 3000, 4000 and 5000 µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: no data

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium, duplicate cultures

DURATION (test without S9)
- Exposure duration: In the test without S9, cells were incubated with barium chloride dihydrate for 10 hours.
Spindel inhibitor: (cytogenetic assays): Colcemid was added and incubation continued for 2 hours.
Stain: (for cytogenetic assays): The cells were then harvested by mitotic shake-off, fixer, and stained with Giemsa.

DURATION (test with S9)
- Exposure duration: In the test with S9, cells were treated with barium chloride dihydrate and S9 for 2 hours, after which the treatment medium was removed and the cells were incubated for 10 to 11 hours in fresh medium.
Spindel inhibitor: (cytogenetic assays): Colcemid was added for the final 2 hours.
Stain: (for cytogenetic assays): The cells were then harvested by mitotic shake-off, fixer, and stained with Giemsa.

NUMBER OF CELLS EVALUATED: One hundred first-division metaphase cells were scored at each dose level. Classes of aberrations included simple (breaks and terminal deletions), complex (rearrangements and translocations), and other (pulverised cells, despiralised chromosomes, and cells containing 10 or more aberrations).

No further details are given.

Evaluation criteria:

no data

Statistics:

CA data are presented as percentage of cells with aberrations. To arrive at a statistical call for a trial, analyses were conducted on both the dose response curve and individual dose points. For a single trial, a statistically significant (P<0.05) difference for one dose point and a significant trend (P<0.015) are considered weak evidence for a positive response; significant differences for two or more doses indicate the trial is positive. A positive trend test in the absence of a statistically significant increase at any one dose results in an equivocal call (Galloway et al., 1987).

Results and discussion

Test results

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

no data

Remarks on result:

other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:

The in vitro chromosome aberration test in CHO cells was negative with and without metabolic activation.