2-ethylhexanoic acid, iron salt

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Research paper study well documented meeting generally accepted scientific principles but not a standard micronucleus test.

Data source

Reference

Reference Type:

publication

Title:

Nuclear aberrations and micronuclei induction in the digestive tract of mice treated with different iron salts.

Author:

Bianchini F, Caderni G, Dolara P, Tanagnelli E

Year:

1988

Bibliographic source:

DOI 10.1002/jat.2550080305 PMID 3171078 Journal of Applied Toxicology 8(3):179-83.

Materials and methods

Principles of method if other than guideline:

This study was undertaken to assess the effects of iron status on the gastrointestinal tract using the nuclear aberrations assay of Wargovich et al. (1983). The current authors interpreted the results by differentiating between micronuclei and nuclear aberrations considering that micronuclei are a specific sign of genetic damage while nuclear aberrations are more unspecific effects related to cellular toxicity. This was because nuclear aberrations may also be associated with substances acting through non-genotoxic mechanisms.- Wargovich MJ, Medline A, Bruce WR (1983). Early histopathologic events to evolution of colon cancer in C57BL/6 and CF1 mice treated with 1,2-dimethylhydrazine. PMID 6575199 J Natl Cancer Inst 71(1):125-31.

GLP compliance:

not specified

Type of assay:

other: micronucleus assay using tissues from gastrointestinal tract

Test material

Test material information

Constituent 1

Reference substance name:

Iron trichloride

EC Number:

231-729-4

EC Name:

Iron trichloride

Cas Number:

7705-08-0

Molecular formula:

FeCl3

IUPAC Name:

iron(3+) trichloride

Details on test material:

Obtained from Merck and reportedly containing ca 20% Fe. The material tested was the hexahydrate of Ferric chloride CAS number 10025-77-1 FeCl3 x 6H2O but this does not affect the chemical species available to the test organisms.

Test animals

Species:

mouse

Strain:

C57BL

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: Charles River, Calco, Como, Italy- Age at study initiation: no data- Weight at study initiation: 17-18 g- Fasting period before study: 12 hours (oral administration) or not fasted (rectal administration)- Housing: no data- Diet (e.g. ad libitum): ad libitum for non-fasting animals- Water (e.g. ad libitum): ad libitum (after treatment)- Acclimation period: no data

Administration / exposure

Route of administration:

other: oral or intrarectal

Vehicle:

- Vehicle(s)/solvent(s) used: physiol. saline; - Concentration of test material in vehicle: 2, 6.5 and 13 mg Fe/kg- Amount of vehicle (if gavage or dermal): 0.2ml

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: 0.2 mL of 10.0-32.2-65.0 mg/kg of FeCl3x6H2O in saline

Duration of treatment / exposure:

one day

Frequency of treatment:

Single treatment

Post exposure period:

24 hours

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:2, 6.5 and 13 mg Fe/kg bwBasis:actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:10.2, 32.5 and 65.0 mg FeCl3x6H2O/kg bwBasis:actual ingested

No. of animals per sex per dose:

4-9

Control animals:

yes

Positive control(s):

2-amino-3-methylimidazo(4,5,f) quinoline (IQ)- Justification for choice of positive control(s): this is a genotoxic chemical with specific intestinal action.- Route of administration: orally to non-fasting mice- Doses / concentrations: 100 and 200 mg/kg bw

Examinations

Tissues and cell types examined:

Colon, duodenum and stomach mucosal cells for oral administration, colon samples after interrectal administration.

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The lowest dose tested was equivalent to a therapeutic dose in iron deficiency anaemia.DETAILS OF SLIDE PREPARATION: colon and duodenum where opened longitudinally and rolled. The forestomach was excised. Specimens were fixed in 10% buffered formalin and processed for histology. Slides with 5 micron thick paraffin sections were stained with Feulgen-fast green.METHOD OF ANALYSIS: Slides were examined and scored for a) micronuclei defined as nuclear fragments not larger than ¼ -1/3 of the diameter of the primary nucleus b) nuclear aberrations comprised of micronuclei, pyknotic nuclei, cytolysosomes and disintegrated nuclei. The forestomach was analysed by observing ca 400 mucosal cells per animal. Mucosal cells lining 20 crypts for colon and 5 crypts for duodenum were analysed per animal beginning from the anal end of the colon and the pyloric end of the duodenum.OTHER:

Evaluation criteria:

Evaluation criteria are not described.

Statistics:

No statistical evaluation was described.

Results and discussion

Test results

Sex:

female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

dose related toxic effects as nuclear aberrations were seen in colons of feeding animals and colon and stomach of fasting animals

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

The reference compound IQ caused an increase of nuclear aberrations and micronuclei, results being presented for effects in the colon. Ferric chloride did not significantly increased the incidence of micronuclei in the stomach, duodenum or colon following oral administration to fasting or non-fasting mice. Nuclear aberrations were slightly increased in the stomach,duodenum and colon of fasting rats receiving ferric chloride. Following intrarectal administration ferric chloride showed cellular toxicity by inducing dose-related increase of nuclear aberrations and produced a slight but statistically significant (p<0.01) increase in micronuclei.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative for induction of micronucleiFerric chloride is not considered to have a significant genotoxic effect on the mouse gastrointestinal tract as measured by induction of micronuclei. An increased incidence of nuclear aberrations was considered evidence of general toxicity.

Executive summary:

This study was undertaken to assess the effects of iron status on the gastrointestinal tract using the nuclear aberrations assay of Wargovich et al. (1983).

Groups of 4 - 9 C57BL/6J female mice received a single dose of ferric chloride either orally or intrarectally (2, 6.5 and 13 mg Fe/kg by both routes) at a volume of 0.2 ml in saline. The lowest dose tested was equivalent to a therapeutic dose in iron deficiency anaemia. The iron compounds were administered to both fasting and non-fasting mice (oral administration only). Samples of fore stomach, duodenum and colon were taken following oral administration and colon samples after intrarectal administration. The samples were examined for micronulei and nuclear aberration postulating that micronuclei are a specific sign of genetic damage while nuclear aberrations are more unspecific effects related to cellular toxicity.

Ferric chloride did not significantly increase the incidence of micronuclei in the stomach, duodenum or colon following oral administration and only marginally in the colon after intrarectal administration. In the stomach, duodenum and colon nuclear aberrations indicating cellular toxicity were increased in fasting mice receiving oral ferric chloride. Following intrarectal administration ferric chloride showed cellular toxicity to the colon producing increase in nuclear aberrations.

Since nuclear aberrations are more unspecific effects related to cellular toxicity ferric chloride does not appear to have a significant genotoxic effect under the conditions of this test system.

Reference

• Wargovich MJ, Medline A, Bruce WR (1983). Early histopathologic events to evolution of colon cancer in C57BL/6 and CF1 mice treated with 1,2-dimethylhydrazine. PMID 6575199 J Natl Cancer Inst 71(1):125-31.