Palladium dichloride

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro DNA damage and/or repair study

Remarks:

Type of genotoxicity: DNA damage and/or repair

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not given

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Although not a standard (guideline) study, it appears well conducted and scientifically acceptable.

Data source

Reference

Reference Type:

publication

Title:

Cytogenetic and oxidative damage induced in human lymphocytes by platinum, rhodium and palladium compounds

Author:

Migliore L, Frenzilli G, Nesti C, Fortaner S and Sabbioni E

Year:

2002

Bibliographic source:

Mutagenesis 17, 411-417

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

A modified alkaline single cell gel electrophoresis (SCGE) assay in human leukocytes, performed according to Singh NP et al. (1988). Exp. Cell Res. 175, 184-191 with some modifications (Klaude M et al (1996). Mutat. Res. 363, 89-96).

GLP compliance:

not specified

Type of assay:

comet assay

Test material

Test material information

Constituent 1

Reference substance name:

Palladium dichloride

EC Number:

231-596-2

EC Name:

Palladium dichloride

Cas Number:

7647-10-1

Molecular formula:

Cl2Pd

IUPAC Name:

palladium dichloride

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): PdCl2
- Physical state: solid
- Impurities (identity and concentrations): 33 metal impurities were determined in 10-2 M solutions; Al, Au, Ba, Bi, Cd, Ce, Co, Cs, Cu, Ge, Ir, La, Nb, Pb, Pd, Rh, Se, Sn, Sr, Th, U and W were present in concentrations ranging from 1.3 (Al) to 0.0007 μg/l (Cs); Ag, As, Be, Ga, Hg, Mn, Mo, Sb, Te, Ti and Zn were below the detection limit (all less than 1 ug/l)

Method

Species / strain

Species / strain / cell type:

primary culture, other: human leukocytes

Details on mammalian cell type (if applicable):

Whole blood obtained from a young, healthy, non-smoking male donor

Metabolic activation:

without

Test concentrations with justification for top dose:

100, 200 and 300 μM (It is unclear whether the units of measurement are mM or μM as the concentrations given in the text and in graphs for other chemicals tested in the same study report the concentrations in μM; however a table detailing the results gives the test concentrations in mM.)

Vehicle / solvent:

Bi-distilled water

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: hydrogen peroxide at concentrations of 50, 100, 150 and 200 μM (or possibly mM)

Details on test system and experimental conditions:

Human leukocytes were mixed with trypan blue and, after 15 min, counted and checked for viability. They were resuspended in RPMI 1640 and treated with the test substance for 2 hr at 37°C and, immediately afterwards, assayed for DNA damage under yellow light to prevent additional DNA damage. 3x10+5 cells (10 μl cell suspension) was added to a slide surface together with agarose. Slides were immersed in ice-cold freshly prepared lysing solution to lyse the cells and allow DNA unfolding. After at least 1 hr at 4°C in the dark, slides were placed on a horizontal electrophoresis unit and the unit filled with buffer to cover the slides. The slides were allowed to set for 20 min to allow DNA unwinding and expression of alkali-labile sites. Electrophoresis was conducted for 20 min at 25 V and slides were gently washed in neutralization buffer to remove alkali and stained with ethidium bromide. Endonuclease III (endo III) and formamidopyrimidine glycosylase (fpg) were used to detect oxidised pyrimidines and damaged purines (including 8-oxoguanine) respectively.The enzymes were diluted in enzyme buffer, placed on gels and covered with coverslips. Slides were put into a moist box and incubated at 37°C for 45 (endo III) or 30 min (fpg).

Evaluation criteria:

Images of 100 randomly selected cells (50 cells from each of 2 replicate slides) were analysed from each sample under a fluorescence microscope using a calibration scale considering 2 variables: nucleus diameter and comet tail length, which includes the nucleus diameter plus tail length. Two independent cultures were performed per experimental point, for a total of 100 cells, and the mean was calculated.

Statistics:

The effects of dose, culture and experiment were evaluated by multifactor analysis of variance (MANOVA). The multiple range test was performed (p<0.05) in order to detect differences in DNA migration among doses.

Results and discussion

Test results

Species / strain:

primary culture, other: human leukocytes

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

Relative viability >80% to prevent potential artefacts due to indirect toxicity-induced damage

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

There were no statistically significant effects on DNA migration or on oxidised pyrimidines and purines, indicating no evidence of DNA damage.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative without metabolic activation

According to a published paper, palladium dichloride did not induce DNA damage in human leukocytes when tested at concentrations of up to 300 μM in the absence of metabolic activation.

Executive summary:

According to a published paper, the ability of palladium dichloride to induce DNA damage in human leukocytes in a modified alkaline single cell gel electrophoresis (SCGE) assay was assessed at concentrations of up to 300 μM, in the absence of a mammalian (S9) metabolic activation system.

There were no statistically significant effects on DNA migration or on oxidised pyrimidines and purines, indicating no DNA damaging effect of treatment.

In conclusion, palladium dichloride did not induce DNA damage in human leukocytes in vitro at concentrations of up to 300 μM in the absence of S9.