Malonic acid

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

GST-P foci assay following diethyl nitrosamine exposure.

Data source

Reference

Reference Type:

publication

Title:

Enhancing effect of various hepatocarcinogens on induction of preneoplastic glutathione S-transferase placental form positive foci in rats—an approach for a new medium-term bioassay system

Author:

Ito, N.; et al

Year:

1988

Bibliographic source:

Carcinogenesis, 9(3) 1, 387–394,

Materials and methods

Principles of method if other than guideline:

The animals in each experiment were divided into three groups. Group 1 was given a single i.p. injection of DEN (200 mg/kg) dissolved in 0.9% NaCl to initiate hepatocarcinogenesis. After 2 weeks on basal diet, they received one of the test compounds in the basal diet (D), drinking water (W), by i.p. or i.v. injection. Animals were subjected to PH at week 3 to maximize any interaction between proliferation and the effects of the compounds tested. Group 2 was given DEN and PH in the same manner as for group 1 without administration of any test compounds. Group 3 animals were injected with 0.9% NaCl instead of DEN solution and then subjected to administration of test compound and PH.Rats in each group were killed for examination at week 8.The doses of test compounds were chosen on the basis of preliminary investigations as permitting >70% survival of rats after PH performed during the administration, or from chronic toxicity data when available.

GLP compliance:

not specified

Type of assay:

other: induction of glutathione S-transferase placental formpositive (GST-P+) foci in the liver

Test material

Test material information

Constituent 1

Reference substance name:

Malonic acid

EC Number:

205-503-0

EC Name:

Malonic acid

Cas Number:

141-82-2

Molecular formula:

C3H4O4

IUPAC Name:

propanedioic acid

Test material form:

solid: crystalline

Details on test material:

Batch No: 20160723Purity: 99.5 %

Specific details on test material used for the study:

Source: Tokyo Chemical Industry Co., Ltd., Tokyo, Japan

Test animals

Species:

rat

Strain:

other: Fischer

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS - Source: Charles River Japan Inc., Atsugi, Japan - Weight at study initiation: — 160 g - Housing: Plastic cages - Diet: (Oriental M, Oriental Yeast Co., Tokyo) ad libitum ENVIRONMENTAL CONDITIONS - Temperature (°C): 24C Animals were housed in an air-conditioned room

Administration / exposure

Route of administration:

oral: feed

Details on exposure:

400 mg/kg/day exposure for 6 weeks via diet

Doses / concentrations

Dose / conc.:

4 000 ppm

No. of animals per sex per dose:

17

Control animals:

yes, concurrent vehicle

Positive control(s):

The study was an an assay of 112 compounds, including a number of known carcinogens.

Examinations

Tissues and cell types examined:

Liver

Details of tissue and slide preparation:

Immediately upon killing, the liver was excised and slices were fixed for immunohistochemical examination of GST-P. Additional sections were fixed for routine staining with H & E. Sections were exposed to anti GST-P and stained for microscopic examination. As a negative control for the specificity of anti-GST-P antibody binding, preimmune rabbit serum was used instead of antiserum.The numbers and areas of GST-P+ foci or areas of > 0.2 mm in diameter were measured uand the results were assessed by comparing the values of foci between group 1 (DEN-test compounds) and group 2 (DEN alone). Group 3 served for the assay of potential to induce GST-P+ foci without prior DEN.

Statistics:

Statistical analysis was carried out using the Student's /-test. Scoring of the results were made on the basis of the difference of P-values between groups 1 and 2: positive, increase at P < 0.05 in either number or area of foci.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Any other information on results incl. tables

GST-P+ foci
DEN – test compound			DEN alone (control)
No rats	No/ cm^2	Area (mm^2)/cm^2	No rats	No/ cm^2	Area (mm^2)/cm^2
17	12.33±3.81	1.04±0.04	17	9.09± 2.05	0.77±0.19

Statistically increased (compared to control group at P<0.01

Applicant's summary and conclusion

Conclusions:

In a study to develop a bioassay for screening potential liver carcinogens, based on the twostep concept of hepatocarcinogenesis, 112 different substances were screened. Carcinogenic potential was scored by comparing the number and area per cm2 of induced glutathione S-transferase placental formpositive (GST-P+) foci in the liver with those of the corresponding control group given DEN alone. Positive was scored for a significant increase in the value of GST-P+ foci, negative for no change or a decrease. Results were compared to reported Salmonella/microsome and long-term carcinogenicity test findings.

Executive summary:

In a study to develop a bioassay for screening potential liver carcinogens, based on the twostep concept of hepatocarcinogenesis, 112 different substances were screened. Carcinogenic potential was scored by comparing the number and area per cm2 of induced glutathione S-transferase placental formpositive (GST-P+) foci in the liver with those of the corresponding control group given DEN alone. Positive was scored for a significant increase in the value of GST-P+ foci, negative for no change or a decrease. Results were compared to reported Salmonella/microsome and long-term carcinogenicity test findings.