Dimethyl sulphide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In a reverse gene mutation assay in bacteria (# OECD 471, GLP), dimethyl sulphide was tested in the bacterial reverse mutation assay (OECD TG 471 and 472) withSalmonella typhimuriumTA98, TA100, TA1535, and TA1537 andEscherichia colistrain WP2uvrA at concentrations up to 5000 µg/plate with and without metabolic activation. The solvent was dimethylsulfoxide (DMSO).  The cytotoxic concentration was >5000 µg/plate. Positive controls produced the expected result. Dimethyl sulphide was not mutagenic under the conditions of the assay (Wagner & Coffman, 1995).

A DNA damage and repair assay (SOS Chromotest) withSalmonella typhimuriumTA1535/pSK1002 was conducted using concentrations of dimethyl sulphide of 0, 0.2, 0.4 or 0.6%, without metabolic activation. The cytotoxic concentration of 0.8% was determined in a preliminary study. No mutagenic activity was observed in this study (Nakamuraet al.,1990).

In a gene mutation assay with L5178Y mouse lymphoma cells performed according to OECD No. 476, dimethylsulphide was tested at concentrations of 0, 0.313, 0.625, 1.25, 2.5, 5 and 10 mM in two independent experiments, with and without a metabolic activation system, the S9 mix, prepared from a liver microsomal fraction (S9 fraction) of rats induced with Aroclor 1254. No noteworthy cytotoxicity was observed at any tested dose-levels, in either experiment, either with or without S9 mix. With and without S9 mix, no noteworthy increase in the mutation frequency was observed at any tested dose-levels in either experiment. Under the experimental conditions of this study, dimethylsulphide did not show any mutagenic activity in the mouse lymphoma assay (Sire, 2010).

Link to relevant study records

Reference

Reference 1

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:

supporting study

Study period:

data not available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment The test was performed only without metabolic activation.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The umu test for detecting SOS-inducing activity (umu gene expression) was carried out essentially as described by Oda et al. (1985)

GLP compliance:

not specified

Type of assay:

SOS/umu assay

Species / strain / cell type:

S. typhimurium, other: TA1535/pSK1002

Details on mammalian cell type (if applicable):

The bacterial strain was transformed with plasmid pSK1002 which is a derivative of pMC1403 carrying the promoter of the umu operon, the umuD and umuC-lacZ- fusion genes

Metabolic activation:

without

Test concentrations with justification for top dose:

0, 0.2, 0.4, 0.6%

Vehicle / solvent:

data not available

Details on test system and experimental conditions:

Lethality tests
Bacteria in logarithmic phase were suspended in 0.1 M phosphate-buffered saline (PBS) at a concentration of about 10e9 cells/ml after washing twice with PBS. Various doses of DMS were added to the suspension. After incubation for 120 min at 37°C, the mixture was diluted with PBS and spread on bouillon plates. The number of colonies was counted after incubation for 20 h at 37°C.

SOS-inducing activity
The umu test for detecting SOS-inducing activity (umu gene expression) was carried out essentially as described previously (Oda et al., 1985). Briefly, an overnight culture of the tester bacterial strain in Luria broth (1% bactotryptone, 0.5% NaCl and 0.5% yeast extract) was diluted 50-fold with fresh TGA medium (1% bactotryptone, 0.5% NaCl and 0.2% glucose; supplemented with 20 mg/l of ampicillin), and incubated at 37°C until the bacterial density at 600 nm reached 0.25-0.30. The culture was divided into 2-ml portions in test tubes, and 0.5 ml of the appropriate concentration of DMS solution in distilled water was added to each tube. After 2 h incubation at 37°C with shaking, the culture was centrifuged to collect cells, which were resuspended in 2.5 ml of PBS and the cell density was read at 600 nm with one portion of the suspension. Using the other portion, the level of beta-galactosidase activity in the cells was assayed by the method of Miller (1972). All tests were performed in duplicate. The tests were carried out in screw-cap test tubes to prevent evaporation.

Species / strain:

S. typhimurium, other: TA1535/pSK1002

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

the tested doses did not exceed toxic levels to the bacteria

Vehicle controls validity:

not specified

Conclusions:

Interpretation of results (migrated information):
negative

dimethyl sulfide did not show umu gene expression at non-toxic doses.

Executive summary:

A DNA damage and repair assay (SOS Chromotest) with Salmonella typhimurium TA1535/pSK1002 was conducted using concentrations of dimethyl sulfide of 0, 0.2, 0.4 or 0.6%, without metabolic activation  The cytotoxic concentration of 0.8% was determined in a preliminary study.  No mutagenic activity was observed in this study.

Reference 2

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian cell gene mutation assay

Target gene:

Thymidine Kinase locus

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Metabolic activation system:

S9 mix, prepared from a liver microsomal fraction (S9 fraction) of rats induced with Aroclor 1254

Test concentrations with justification for top dose:

0, 0.313, 0.625, 1.25, 2.5, 5 and 10 mM

Vehicle / solvent:

DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Without S9 mix: Methylmethane Sulfonate (MMS), with S9 mix: Cyclophosphamide (CPA)

Details on test system and experimental conditions:

After a preliminary toxicity test, DIMETHYLSULPHIDE was tested in two independent experiments, with and without a metabolic activation system, the S9 mix, prepared from a liver microsomal fraction (S9 fraction) of rats induced with Aroclor 1254.
Approximately 0.5 x 106 (3-hour treatment) or 0.15 x 106 (24-hour treatment) cells/mL in 20 mL culture medium with 5% horse serum were exposed to the test or control items, in the presence or absence of S9 mix (final concentration of S9 fraction 2%), at 37°C. For the 24-hour treatment, the incubation at 37°C was performed with a gentle shaking.

Cytotoxicity was measured by assessment of adjusted relative total growth (Adj. RTG) and relative suspension growth (Adj. RSG) as well as cloning efficiency following the expression time (CE2).
The number of mutant clones (differentiating small and large colonies) were checked after the expression of the mutant phenotype.

Evaluation criteria:

IWGT recommendations were followed for the determination of a positive result which should fulfill the following criteria:
. at least at one dose-level the mutation frequency minus the mutation frequency of the vehicle control equals or exceeds the global evaluation factor (126 x 10-6 for the microtiter method),
. and a dose-related trend is demonstrated by a statistically significant trend test.

Unless considered as clearly positive, the reproducibility of a positive effect should be confirmed.
Noteworthy increases in the mutation frequency observed only at high levels of cytotoxicity (RTG lower than 10%), but with no evidence of mutagenicity at dose-levels with RTG between 10 and 20%, is considered as positive result.

A test item may be determined to be non-mutagenic when there is no culture showing an Adj. RTG value between 10-20% if (e):
. there is at least one negative data point between 20 and 25% Adj. RTG and no evidence on mutagenicity in a series of data points between 100 to 20% Adj. RTG,
. there is no evidence of mutagenicity in a series of data points between 100 to 25% and there is also a negative data point between 10 and 1% Adj. RTG.

Statistics:

Not appropriate

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

PRELIMINARY TOXICITY TEST
The test item was freely soluble in the vehicle (DMSO) at 124.26 mg/mL. Using a treatment volume of 100 µL/20mL of culture medium, the final dose-level of 10 mM (corresponding to 621.30 µg/mL) showed no precipitate. At this dose-level, the pH was approximately 7.1 (as for the vehicle control) and the osmolality equal to 376 mOsm/kg H2O (as for the vehicle control).
The dose-levels used for treatment were 0.156, 0.313, 0.625, 1.25, 2.5, 5 and 10 mM (corresponding to 9.71, 19.42, 38.83, 77.66, 155.33, 310.65 and 621.3 µg/mL).
No noteworthy toxicity was noted at any tested dose-levels, either following the 3-hour treatment with and without S9 mix, or following the 24-hour treatment without S9 mix.

MUTAGENICITY EXPERIMENTS (Tables 1 to 4, attached document)
The cloning efficiencies CE2 and the mutation frequencies (see § Study plan adherence) of the vehicle and positive controls were as specified in acceptance criteria. The study was therefore considered valid.
Since the test item was freely soluble and non-toxic in the preliminary test, the highest dose-level selected for the main test was 10 mM, according to the criteria specified in the international guidelines.
Using a treatment volume of 100 µL/20 mL, the selected dose-levels were 0.313, 0.625, 1.25, 2.5, 5 and 10 mM for both mutagenicity experiments with and without S9 mix.

Cytotoxicity
No noteworthy cytotoxicity was observed at any tested dose-levels, in either experiment, either with or without S9 mix.

Mutagenicity
Without S9 mix, no noteworthy increase in the mutation frequency was observed at any tested dose-levels, either following the 3-hour treatment or following the 24-hour treatment.
With S9 mix, no noteworthy increase in the mutation frequency was observed at any tested dose levels in either experiment.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

DIMETHYLSULPHIDE did not show any mutagenic activity in the mouse lymphoma assay

Executive summary:

The potential of dimethylsulphide to induce mutations at the TK (Thymidine Kinase) locus of L5178Y mouse lymphoma cells was evaluatedi in a study performed according to OECD No. 476 and in compliance with GLP. After a preliminary toxicity test, dimethylsulphide was tested at concentrations of 0, 0.313, 0.625, 1.25, 2.5, 5 and 10 mM in two independent experiments, with and without a metabolic activation system, the S9 mix, prepared from a liver microsomal fraction (S9 fraction) of rats induced with Aroclor 1254.

The cloning efficiencies CE₂and the mutation frequencies of the vehicle and positive controls were mainly as specified in acceptance criteria. The study was therefore considered valid. No noteworthy cytotoxicity was observed at any tested dose-levels, in either experiment, either with or without S9 mix. With and without S9 mix, no noteworthy increase in the mutation frequency was observed at any tested dose-levels in either experiment.

Under the experimental conditions of this study, dimethylsulphide did not show any mutagenic activity in the mouse lymphoma assay.

Reference 3

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 15-AUG-1995 to 18-OCT-1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to OECD guidelines and GLP

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Target gene:

different mutation in various gene in the histidine operon

Species / strain / cell type:

other: Salmonella typhimurium TA 98, 100, 1535, 1537 and Escherichia coli WP2 uvrA

Metabolic activation:

with and without

Metabolic activation system:

Arochlor 1254-induced rat liver S9

Test concentrations with justification for top dose:

0, 100, 333, 1000, 3333, 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: DMSO was selected as the solvent of choice based on the solubility of the test article and compatibility with the target cells. The test article was soluble in DMSO at approximately 500 mg/L, the maximum concentration test.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: WITH ACTIVATION: all Salmonella strain = 2 aminoanthracene (1µg/pl), Ecoli = 2 aminoanthracene (10µg/pl) // WITHOUT ACTIVATION: TA98 = 2-nitrofluorene (1µg/pl), TA100 & TA1535 = sodium azide (1µg/pl), TA1537 = 2-aminoacridine (75 µg/pl), WP2 uvrA = methyl

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation


DURATION
- Preincubation period: 60 +/- 2 min at 37 +/-2 °C
- Exposure duration: 48 to 72 hours at 37 +/- 2°C


NUMBER OF REPLICATES: three


DETERMINATION OF CYTOTOXICITY
- Method: the condition of the bacterial background lawn was evaluated for evidence of test article toxicity by using a dissecting microscope


OTHER:
Scoring method: revertant colonies for a given tester strain and activation condition were counted either entirely by automated colony counter or entirely by hand unless the assay was the preliminary toxicity assay or the plate exhibited toxicity. Plates with sufficient test article precipitate to interfere with automated colony counting were counted manually.

Evaluation criteria:

Data sets for strains TA1535 and TA1537 were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than three times the mean vehicle control value.
Data sets for strains TA98, TA100 and WP2 uvrA were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than two times the mean vehicle control value

Statistics:

not applicable

Species / strain:

other: Salmonella typhimurium TA 98, 100, 1535, 1537 and Escherichia coli WP2 uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: no precipitate was observed
- Effects of pH, Effects of osmolality, Evaporation from medium,Other confounding effects: data not available


RANGE-FINDING/SCREENING STUDIES: In the preliminary toxicity assay, the maximum dose level tested was 5000 µg/plate. Neither precipitate nor appreciale toxicity was observed.


COMPARISON WITH HISTORICAL CONTROL DATA: the response of the vehicle control group and of the positive control groups are in the range of historical data

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Table 1: Average number of revertants per plate (mean of 3 plates) – Experiment B1/B2

	TA98			TA100			TA1535
Conc. µg/plate	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	15	29	no	134	134	no	14	10	no
100	17	31	no	143	120	no	7	11	no
333	17	29	no	133	145	no	7	14	no
1000	19	25	no	125	143	no	11	9	no
3333	12	30	no	124	120	no	7	9	no
5000	15	31	no	114	135	no	11	11	no
Positive control	432	1202	no	482	1233	no	500	126	no

*solvent control with DMSO

	TA1537			WP2 uvrA
Conc. µg/plate	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	9	7	no	20	15	no
100	7	10	no	24	11	no
333	6	10	no	19	18	no
1000	6	8	no	12	20	no
3333	7	9	no	22	14	no
5000	6	8	no	20	17	no
Positive control	575	124	no	432	246	no

Table 2: Average number of revertants per plate (mean of 3 plates) – Experiment B3

	TA98			TA100			TA1535
Conc. µg/plate	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	17	22	no	120	131	no	9	10	no
100	14	17	no	99	123	no	6	11	no
333	14	19	no	109	137	no	8	10	no
1000	20	22	no	113	136	no	7	9	no
3333	14	28	no	116	126	no	8	12	no
5000	17	25	no	96	132	no	7	9	no
Positive control	415	1141	no	468	1011	no	311	108	no

*solvent control with DMSO

	TA1537			WP2 uvrA
Conc. µg/plate	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	7	5	no	15	14	no
100	4	4	no	12	16	no
333	6	5	no	13	18	no
1000	3	9	no	13	14	no
3333	5	7	no	12	15	no
5000	2	4	no	9	17	no
Positive control	461	123	no	668	82	no

Conclusions:

Interpretation of results (migrated information):
negative

Dimethyl sulfide was concluded to be negative in the Salmonella / Escherichi coli closed-phase preincubation mutagenicity assay with an independent repeat assay.

Executive summary:

In a reverse gene mutation assay in bacteria (similar to OECD testing guideline 471 and according to GLP), Salmonella typhimurium TA 98, 100, 1535, 1537 and Escherichia coli WP2 uvrA were exposed to Dimethyl sulfide in DMSO at concentrations of 0, 100, 333, 1000, 3333 and 5000 µg/plate in the presence and absence of mammalian metabolic activation by the preincubation method . Neither precipitate nor appreciable toxicity was observed. With dimethyl sulfide, no positive responses were observed in either in the presence or in the absence of activation. The positive controls induced the appropriate responses in the corresponding strains. Dimethyl sulfide was concluded to be negative in the Salmonella / Escherichi coli closed-phase preincubation mutagenicity assay with an independent repeat assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

A mouse micronucleus study (#OECD 474 and GLP) with dimethyl sulphide was conducted in male and female animals at gavage doses of 0, 1250, 2500, or 5000 mg/kg. Clinical signs of lethargy were observed on the day following dosing but no deaths occurred in any group. Five mice per sex from each group were sacrificed at 24, 48, and 72 hours after dose administration. A total of 1000 polychromatic erythrocytes from bone-marrow suspension were scored for the presence of micronuclei and the proportion of PCEs to total erythrocytes was recorded. The incidence of micronucleated polychromatic erythrocytes (PCEs) in DMS-treated groups was not significantly increased relative to vehicle controls in either male or female mice regardless of dose level or bone marrow collection time. The positive control, cyclophosphamide, induced a significant increase in micronuclei relative to the vehicle control (Putman et al., 1995).

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 18-MAY-1995 to 05-OCT-1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed similarly to OECD guidelines and according to GLP

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

yes

Remarks:

only 1000 cells scored per animal

GLP compliance:

yes

Type of assay:

micronucleus assay

Species:

mouse

Strain:

ICR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley, Inc., Frederick, MD
- Age at study initiation: 6 to 8 weeks old
- Weight at study initiation: males were 27.4 to 35.8 grams and females were 24.5 to 30.7 grams
- Assigned to test groups randomly: yes, according to a computer-generated program which is based on distribution according to body weight
- Fasting period before study: data not available
- Housing: mice of the same sex were housed up to five per cage in plastic autoclavable cages with filter tops. Heat-treated hardwood chips were used for bedding
- Diet: certificed laboratory rodent chow, ad libitum
- Water: tap water, ad libitum
- Acclimation period: animals were quarantined for no less than 5 days after receipt


ENVIRONMENTAL CONDITIONS
- Temperature: 74 +/- 6°F (23.3 °C)
- Humidity: 50 +/- 20%
- Air changes: data not available
- Photoperiod: 12 hour light/dark cycle


IN-LIFE DATES: data not available

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: the test article was soluble in corn oil at a concentration of 250 mg/mL, the maximum concentration tested
- Concentration of test material in vehicle: the maximum concentration was 250 mg/mL
- Amount of vehicle: 20 mL/kg
- Lot/batch no.: data not available
- Purity: data not available

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: data not available

Duration of treatment / exposure:

Test substance was given once and bone marrow cells were collected 24, 48 and 72 hours after treatment

Frequency of treatment:

once

Post exposure period:

bone marrow cells were collected 24, 48 and 72 hours after treatment

Remarks:

Doses / Concentrations:
0, 1250, 2500 and 5000 mg/kg
Basis:
nominal conc.

No. of animals per sex per dose:

5 animals per sex and per collection time

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide
- Justification for choice of positive control(s): cited in the OECD guideline
- Route of administration: oral gavage
- Doses / concentrations: 60 mg/kg

Tissues and cell types examined:

Using oil immersion, 1000 polychromatic erythrocytes were scored for the presence of micronuclei (for each mouse and treatment group).
The proportion of polychromatic erythrocytes to total erythrocytes was also recorded per 1000 erythrocytes.

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: based on a preliminary toxicity assay (in which no mortality was observed at 5000 mg/kg)


DETAILS OF SLIDE PREPARATION:
the mice were sacrificed by CO2 asphyxiation. The bone marrow cells were extracted and prepared. The slides were fixed in methanol, stained with May-Gruenwald-Giemsa and permanently mounted.

Evaluation criteria:

The test article was considered to induce a positive response if a treatment-related increase in micronucleated polychromatic erythrocytes was observed and one or more doses were statistically elevated relative to the vehicle control at any sampling time.
If a single treatment group was significantly elevated at one sacrifice time with no evidence of a dose-response, the assay was considered a suspect or unconfirmed positive and a repeat-assay recommended.
The test article was considered negative if no statistically significant increase in micronucleated polychromatic erythrocytes above the concurrent vehicle control was observed at any sampling time.

Statistics:

Statistically significance was determined using the Kastenbaum-Bowman tables which are based on the binomial distribution. All analyses were performed separately for each sex and sampling time.

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

lethargy in males and females exposed at 1250, 2500 and 5000 mg/kg

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: for the toxicity study, dimethyl sulfide was administrated by oral gavage to male and female mice at 3000, 3500, 4000 and 5000 mg/kg
- Solubility: the test article was soluble in corn oil at the maximum test concentration of 250 mg/mL
- Clinical signs of toxicity in test animals: lethargy in males and females was observed at all dose levels on the day following dose administration
- Evidence of cytotoxicity in tissue analyzed: not examined


RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): the number of micronucleated polychromatic erythrocytes per 1000 polychromatic erythrocytes in test article treated groups was not statistically increased relative to their respective vehicle control in either male or female mice regardless of dose levels or bone marrow collection time. Cyclophosphamide induced a significant increase in micronucleated polychromatic erythrocytes in both male and female mice
- Appropriateness of dose levels and route: up to 5000 mg/kg

Table 1: summary of bone marrow micronucleus study using dimethyl sulfide

Treatment	Sex	Time (hr)	Number of mice	PCE / total erythrocytes	Micronucleated polychromatic erythrocytes
					No. Per 1000 PCE’s (Mean)	No. Per PCE’s scored
Corn oil	M	24 48 72	5 5 5	0.53 0.58 0.57	0.8 1.4 0.8	4 \ 5000 7 \ 5000 4 \ 5000
	F	24 48 72	5 5 5	0.70 0.59 0.61	2.0 1.0 1.2	10 \ 5000 5 \ 5000 6 \ 5000
1250 mg/kg	M	24 48 72	5 5 5	0.55 0.62 0.61	0.4 0.8 1.0	2 \ 5000 4 \ 5000 5 \ 5000
	F	24 48 72	5 5 5	0.64 0.56 0.63	0.6 1.6 1.4	3 \ 5000 8 \ 5000 7 \ 5000
2500 mg/kg	M	24 48 72	5 5 5	0.56 0.56 0.63	1.0 1.6 0.6	5 \ 5000 8 \ 5000 3 \ 5000
	F	24 48 72	5 5 5	0.66 0.55 0.60	0.4 0.6 1.4	2 \ 5000 3 \ 5000 7 \ 5000
5000 mg/kg	M	24 48 72	5 5 5	0.55 0.58 0.51	0.2 0.8 1.2	1 \ 5000 4 \ 5000 6 \ 5000
	F	24 48 72	5 5 5	0.67 0.53 0.66	0.8 0.8 1.8	4 \ 5000 4 \ 5000 9 \ 5000
CP 60 mg/kg	M	24	5	0.54	17.4	87 \ 5000 *
	F	24	5	0.46	34.4	172 \ 5000 *

* p= 0.05 (Kastenbaum-Bowman Tables)

Conclusions:

Interpretation of results (migrated information): negative
Dimethyl sulfide did not induce a significant increase in the incidence of micronucleated polychromated erythrocytes in bone marrow and was concluded to be negative in the micronucleus test using male and female ICR mice.

Executive summary:

In a ICR mouse bone marrow micronucleus assay performed according to the OECD guideline # c474 and GLP, 5 animals per sex per collection time and per dose level were treated once by oral gavage with dimethyl sulfide at doses of 0, 1250, 2500 and 5000 mg/kg bw.  Bone marrow cells were harvested at 24, 48 and 72 post-treatment.  The vehicle was corn oil.

Lethargy was observed during the study, in males and females at all dose levels. Reduction up to 11% in the ratio of polychromatic erythrocytes to total erythrocytes were observed in some of the test article treated groups relative to their respective vehicle control. Dimethyl sulfide was tested at an adequate dose (up to 5000 mg/kg). The positive control induced the appropriate response.  There was not a significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow after any treatment time.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Justification for classification or non-classification

Dimethyl sulphide is considered not to have any mutagenic potential. No classification is required according to Regulation (EC) No 1272/2008 and Directive 67/548/EEC.