Zinc bromide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

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:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Justification for data waiving:

other:

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2007

Materials and methods

Test guideline

Qualifier:

no guideline followed

Deviations:

not applicable

Principles of method if other than guideline:

The clastogenic activity of zinc chloride was determined by studying chromosome aberrations in human dental pulp cells in vitro, both in the presence and absence of exogenous metabolic activation.

GLP compliance:

no

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Zinc chloride

EC Number:

231-592-0

EC Name:

Zinc chloride

Cas Number:

7646-85-7

IUPAC Name:

zinc dichloride

Details on test material:

- Name of test material (as cited in study report): Zinc chloride
- Analytical purity: 99.9%

Method

Target gene:

Not applicable

Species / strain

Species / strain / cell type:

other: Human dental pulp cells (D824 cells)

Details on mammalian cell type (if applicable):

- Dental pulp tissue obtained from a lower third molar extracted from a 22 years old woman
- Type and identity of media: α-minimum essential medium supplemented with 20 % fetal bovine serum (FBS), 100 µM L-ascorbic acid phosphate magnesium salt n-hydrate, 2 mM L-glutamine, 0.22% NaHCO3 and 100 µg/mL streptomycin

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

5% rat liver postmitochondrial supernatant (PMS) mixture

Test concentrations with justification for top dose:

30, 100 and 300 µM

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO (60mM)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

None

Migrated to IUCLID6: 50 µM

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium


DURATION
- Preincubation period: Overnight
- Exposure duration: 3 h


NUMBER OF REPLICATIONS: Triplicate


NUMBER OF CELLS EVALUATED: 1.6×10 (5) cells/dish


DETERMINATION OF CYTOTOXICITY: Yes
- Method: The cytotoxicity of the test material was determined as the number of cells treated with the test material relative to the number of cells in the control cultures×100


OTHER EXAMINATIONS:
- Determination of polyploidy: Yes


OTHER: The pH range of the culture media containing the highest concentrations of test agents was approximately 7.2–7.5.

Evaluation criteria:

No data

Statistics:

χ2-test was used to assess the significance of the difference in the incidences of chromosome aberrations between control cultures and cultures treated with test agents. The level of significance in the statistical analysis was determined at p<0.05.

Results and discussion

Test results

Species / strain:

other: Human dental pulp cells (D824 cells)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

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

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Chromosome aberrations in D824 cells induced by treatment with ZnCl2 for 3 h and 30 h:

Test material	Time	Concentration	Relative cell number (%)	Number of metaphases scored	Type of structural aberrations(a) (%)								Aberrant metaphases (%)	Polyploidy and endoreduplication (%)
					ctg	csg	ctb	csb	cte	D	O	F
Control	3 h	0	100	500	0.8	0	0	0	0	0	0	0	0.8	2
Zinc chloride (µM)		30	91	100	0	0	0	0	0	0	0	0	0	0
		100	74	100	1	0	0	0	0	0	0	0	1	1
		300	77	100	0	0	0	0	0	0	0	0	0	1
Control	30 h	0	100	500	1	0	0	0	0	0	0	0	1	2
Zinc chloride (µM)		30	85	100	0	0	0	0	0	0	0	0	0	2
		100	77	100	1	0	0	0	0	0	0	0	1	2
		300	74	200	3.5	0	0.5	0	0	0	0	0	4	0

a = ctg, chromatid gaps; csg, chromosome gaps; ctb, chromatid breaks; csb, chromosome breaks; cte, chromatid exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations.

 

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the test conditions, the test material was considered to be non-clastogenic to human dental pulp cells in vitro.

Executive summary:

A study was conducted to investigate the ability of Zinc chloride to induce chromosome aberrations in human dental pulp cells.

Human dental pulp cells (D824 cells) treated with the test material, were evaluated for chromosome aberrations at up to 3 dose levels, together with vehicle and positive controls. Rat liver (5%) post mitochondrial supernatant mixture was used as the exogenous metabolic activator. Ability to induce chromosome aberrations was examined in cells treated with test material for 3 and 30 h.

The test material failed to induce chromosome aberrations in the presence or absence of exogenous metabolic activation. The percentages of cells with polyploid or endoreduplication were not enhanced by test material.

 

Under the test conditions, the test material was considered to be non-clastogenic to human dental pulp cells in vitro.