Valeraldehyde

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented publication which meets basic scientific principles (limited reporting)

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 482 (Genetic Toxicology: DNA Damage and Repair, Unscheduled DNA Synthesis in Mammalian Cells In Vitro)

Deviations:

yes

Remarks:

: limited reporting

Principles of method if other than guideline:

No guideline stated but the test method used is similar to OECD test guideline 482. Five n-alkanals were tested.

GLP compliance:

no

Type of assay:

DNA damage and repair assay, unscheduled DNA synthesis in mammalian cells in vitro

Test material

Test material information

Constituent 1

Reference substance name:

Valeraldehyde

EC Number:

203-784-4

EC Name:

Valeraldehyde

Cas Number:

110-62-3

Molecular formula:

C5H10O

IUPAC Name:

pentanal

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): pentanal (purchased from E. Merck, Darmstadt, Germany)
- Analytical purity: 98%
- no further information on test substance

Method

Species / strain

Species / strain / cell type:

hepatocytes: primary cultures from livers of two human subjects

Details on mammalian cell type (if applicable):

- primary human hepatocyte cultures were isolated from apparently healthy fragments of human livers obtained from one male and one femal human subject. Liver fragments were discarded during the course of prescribed surgery. As checked by both macroscopic and histological examinations, these fragments were devoid of appreciable alterations.
- primary hepatocytes were isolated by collagenase perfusion. The portion of viable cells was 65% and 83% respectively.
- Type and identity of media: Williams' medium E

Test concentrations with justification for top dose:

0, 3, 10, and 30 mM (0, 0.26, 0.86, and 2.58 mg/mL); in addition 100 mM (8.61 mg/mL) for the determination of cytotoxicity

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: non

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-dimethylnitrosamine

Remarks:

Migrated to IUCLID6: concentration: 5 mM (0.37 mg/mL)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 20 h; cells were simultaneously exposed to test compound and tritiated thymidine (10 µCi/mL [methyl-3H]thymidine))
- Expression time (cells in growth medium): 20 h
- Fixation time (start of exposure up to fixation or harvest of cells): 20 h

STAIN (for cytogenetic assays): hematoxylin and eosin (after development of autoradiographs)

NUMBER OF REPLICATIONS: two cultures from distinct rats each

NUMBER OF CELLS EVALUATED: total of 200; 100 (2 slides) per culture

DETERMINATION OF CYTOTOXICITY
- Method: determination of viability (percent survival) by counting cells (1000/dish) after staining exposed cell cultures with 0.4% trypan blue

Evaluation criteria:

A compound is considered positive if a dose-dependent increase is observed in net nuclear grains for at least two points and both increased points are above the justified laboratory-specific threshold, and/or statistical significance is demonstrated for both points (Internation Workshop on Standardization of Genotoxicity Test Procedures, Melbourne, 1992)
An absolute threshold for a positive response (i.e. 5 net nuclear grains) was not used.

Statistics:

Statistical significance compared to controls was assessed by Student's t-test (two-tailed)

Results and discussion

Test results

Species / strain:

hepatocytes: primary cultures from livers of two human subjects

Metabolic activation:

not specified

Genotoxicity:

negative

Remarks:

see table below

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

see table below

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

True negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Results of UDS test with primary human hepatocytes

 

Treatment	Concentration [mg/mL]	% Cell survival		NUC* (mean ± SD)	CYT* (mean ± SD)	NNG* (mean ± SD)	% Repair**
		Subject 1	Subject 2
Controls		92	97	8.88 ± 3.36	8.33 ± 3.12	0.55 ± 1.69	1
Valeraldehyde	0.26	91	95	10.01 ± 3.33	9.16 ± 2.40	0.85 ± 2.07	6
	0.86	90	95	11.40 ± 4.21	10.54 ± 3.84	0.86 ±2.63	5
	2.58	87	91	9.09 ± 5.12	8.00 ± 4.25	1.09 ± 3.02	8
DMNA****	0.37	80	93	24.64 ± 5.38	6.51 ± 3.94	18.13 ± 4.95***	90

 

* NUC: nuclear grain count; CYT: cytoplasmic grain count; NNG:net nuclear grains

** Percentage repair is the percentage of cells with net nuclear labeling ≥ 5 grains

*** p < 0.001

**** DMNA: N,N-Dimethylnitrosamine

No increase of net nuclear grains was observed in valeraldehyde treated cell cultures. The number of cells in repair was always below 10%.  

Applicant's summary and conclusion

Conclusions:

In a UDS test similar to OECD test guideline 482, no increase in DNA repair could be observed after treatment of primary human hepatocytes with valeraldehyde. Valeraldehyde was demonstrated to be negative and not to induce a mutagenic response in primary human hepatocytes.

Executive summary:

In an unscheduled DNA synthesis assay, primary cultures of human hepatocyte were exposed to valeraldehyde (purity 98%) at concentrations of 0, 0.26, 0.86, and 2.58 mg/ml for 20 h in the presence of tritium labeled thymidine. Human hepatocytes were obtained from discarded liver fragments during prescribed surgery of two human subjects.

 

Valeraldehyde was tested up to concentrations indicating the beginning of cytotoxicity. Treated cells did not show any statistically significant increases in DNA synthesis. The positive controls induced the appropriate response. There was no evidence that unscheduled DNA synthesis, as determined by radioactive tracer procedures (nuclear silver grain counts) was induced. Primary cultures of human hepatocytes were demonstrated to be negative in this unscheduled DNA synthesis assay (Martelli 1994).

 

This study is classified as acceptable. It satisfies the requirement of Test Guideline OECD 482 for DNA damage and repair (deviation: limited reporting).