Cysteine hydrochloride

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1987 or before

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study. However the short comings are: no GLP, purity not given although checked, application volume is not reported, no data on temperature

Data source

Reference

Reference Type:

publication

Title:

Micronucleus Tests in Mice on 39 Food Additives and Eight Miscellaneous Chemicals

Author:

Hayashi M, Kishi M, Sofuni T, Ishidate M

Year:

1988

Bibliographic source:

Fd Chem. Toxic. 26: 487-500

Materials and methods

Principles of method if other than guideline:

In vivo micronucleus test with mouse bone marrow cells

GLP compliance:

no

Type of assay:

mammalian bone marrow chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

L-Cysteine Hydrochloride Monohydrate

Cas Number:

175.63

Molecular formula:

C3H7NO2S·HCl·H2O

IUPAC Name:

L-Cysteine Hydrochloride Monohydrate

Test material form:

solid: granular

Test animals

Species:

mouse

Strain:

other: ddY mice

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Shizuoka Agricultural Cooperative Association for Laboratory Animals, Shizuoka
- Age at study initiation: 8 weeks
- Diet: food pellets CE-2, ad libitum
- Water: ad libitum
ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

saline (probably 0.9 % NaCl solution)

Duration of treatment / exposure:

24 h

Frequency of treatment:

one intraperitoneal injection

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

500 mg/kg bw (total dose)

Doses / concentrations 2

Dose / conc.:

250 mg/kg bw (total dose)

Doses / concentrations 3

Dose / conc.:

125 mg/kg bw (total dose)

No. of animals per sex per dose:

Two and six male mice per group were used in the pilot and full-scale tests, respectively.

Control animals:

other:

Positive control(s):

Mitomycin C

Examinations

Tissues and cell types examined:

1000 polychromatic erythrocytes per mouse were scored. The number of micronucleated polychromatic erythrocytes, the number of polychromatic erythrocytes and the total number of erythrocytes
were evaluated.

Details of tissue and slide preparation:

DETAILS OF SLIDE PREPARATION: 24 hours after the intraperitoeal administration the animals
were killed and the femoral marrow cells were flushed out with foetal bovine serum and smeared on clean glass slides. Cells were fixed with methanol for 5 min, and stained with Acridine Orange for the pilot experiment and with Giemsa for the full-scale test.
METHOD OF ANALYSIS: 1000 polychromatic erythrocytes per mouse were scored using a light
microscope, and the number of micronucleated polychromatic erythrocytes was recorded. The proportion of polychromatic erythrocytes among the total erythrocytes was also evaluated by observing 1000 erythrocytes on the same slide.

Evaluation criteria:

A two stage statisticall procedure was used. In the first step of the procedure, the frequency of MNPCEs in each tratment group was compared with the binominal distribution specified by histrical control data from the lab. In the second step, teh dose-response relationhip wsa testd by the Cochran-Armitage trend test.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative Single intraperitoneal dosages of 0, 125, 250 and 500 mg L-cystein hydrochloride/kg bw. were administered to groups of 6 male mice. 24 hr later femoral marrow cells were taken for evaluation. No in vivo mutagenicity was found.
As the study is in vivo and on the background of the results of the carcinogenicity study it can be stated:
(1) that the substance L-Cysteine hydrochloride is not mutagenic for mammals and
(2) the study can be used to fulfill the information requirement of Annex VIII 8.4: "8.4. Appropriate in vivo mutagenicity studies shall be considered in case of a positive result in any of the genotoxicity studies in Annex VII or VIII."

Executive summary:

L-Cystein hydrochloride was injected ip to mice in a micronucleus test. Eight-week old male ddY mice were used. The maximum dose of the test compound was determined by a pilot experiment. The sampling time after the sdministration was 24 hr. The compound was administered by one intraperitoneal injection. Groups of 6 male mice were administered single dosages of 0, 125, 250 and 500 mg/kg bw.. No mortality was observed. L-cystein hydrochloride was tested negative in the bone marrow micronucleus
test in mice.