Methyl methanesulphonate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

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:

Data is from peer- reviewed journal

Data source

Reference

Reference Type:

publication

Title:

Differential susceptibility of rat embryos to Methyl Methansulfonateduring the pregastrulation period

Author:

Ryohei Yokoi, Satoshi Suda, Kazuo Kobayashi, Junji Kuroda, Hiroshi Kusama, Hiroshi Kagami and Tamao Ono

Year:

2007

Bibliographic source:

The Journal of Toxicologcal Sciences, Vol 32, No.5 495-503,2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: as below

Principles of method if other than guideline:

Embryonic and placental development toxicityy study of Methyl Methansulfonate (MMS) in rat

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl methanesulphonate

EC Number:

200-625-0

EC Name:

Methyl methanesulphonate

Cas Number:

66-27-3

Molecular formula:

C2H6O3S

IUPAC Name:

methyl methanesulfonate

Details on test material:

- Name of test material (as cited in study report): Methyl Methansulfonate (MMS)
- Molecular formula (if other than submission substance): C2H6O3S
- Molecular weight (if other than submission substance): 110.1324 g/mole
- Substance type: Organic
- Physical state: Solid
- Impurities (identity and concentrations): 00.1 %

Specific details on test material used for the study:

- Name of test material (as cited in study report): Methyl Methansulfonate (MMS)
- Molecular formula (if other than submission substance): C2H6O3S
- Molecular weight (if other than submission substance): 110.1324 g/mole
- Substance type: Organic
- Physical state: Solid
- Impurities (identity and concentrations): 00.1 %

Test animals

Species:

rat

Strain:

other: Crj:CD (SD)IGS (SD)

Details on test animals or test system and environmental conditions:

- Source: Charles River Japan (Shiga, Japan)
- Age at study initiation: No data available
- Weight at study initiation: No data available
- Fasting period before study: No data available
- Housing: Animals were housed individually in a stainless steel mesh cages (260by 230 by 180 mm) with barrier facility
- Diet (e.g. ad libitum): Pellet diet, ad libitum
- Water (e.g. ad libitum): Tap water, ad libitum
- Acclimation period: Yes, period not mention.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 2˚C
- Humidity (%): 55 ± 15 %
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): 12 hr light / 12 hr dark cycle (light from 0800 to 2000 hr)

IN-LIFE DATES: From: To: No data available

Administration / exposure

Route of administration:

oral: gavage

Type of inhalation exposure (if applicable):

not specified

Vehicle:

water

Remarks:

distilled

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Methyl Methansulfonate (MMS) was dissolved in distilled water and prepared freshly daily.

VEHICLE
- Justification for use and choice of vehicle (if other than water): Distilled water
- Concentration in vehicle:0 and 200 mg/kg/bw/day
- Amount of vehicle (if gavage): No data available
- Lot/batch no. (if required): No data available
- Purity: No data available

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- M/F ratio per cage: 1:1 ratio
- Length of cohabitation: Overnight
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy Presence of a vaginal plug or of sperm in the vaginal smear on the morning after mating is referred as day 0 of gestation.
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility. No data available
- Further matings after two unsuccessful attempts: [no / yes (explain)] No data available
- After successful mating each pregnant female was caged (how): No data available
- Any other deviations from standard protocol: No data available

Duration of treatment / exposure:

7 days

Frequency of treatment:

Daily

Duration of test:

20 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

200 mg/kg bw/day

No. of animals per sex per dose:

Total: 68
0 mg/kg body weight /day: 8 female
200 mg/kg body weight /day: GD0 :9 female
200 mg/kg body weight /day: GD1 :8 female
200 mg/kg body weight /day: GD2 :9 female
200 mg/kg body weight /day: GD3 :8 female
200 mg/kg body weight /day: GD4 :8 female
200 mg/kg body weight /day: GD5 :9 female
200 mg/kg body weight /day: GD6 :9 female

Control animals:

yes, concurrent vehicle

Details on study design:

not specified

Examinations

Maternal examinations:

Erythrocyte parameters, Number of pregnant female, Pre-implantation and post implantation loss, Intrathoracic and intraperitoneal organs and Gross abnormalities were examined.

Ovaries and uterine content:

Number of live fetuses, Number of implantation sites and number of corpora lutea was examined.

Fetal examinations:

Number of live and deid fetuses, fetal body weigth, placental weight, External malformation in live fetuses, frequency of visceral malformations and variations in live feuses, frequency of skeletal malormation and progress of ossification in live fetuses were examined.

Statistics:

Statisical analysis were done by using Mann-Whitney rank sum test with the Yates corection for ties to compare the number of corpora lutea, the number of implatations, the number of live fetuses, fetal weight, placental weight, hematologic parameters, indices of postimplantation or variations. The chi-square test was useed to analyze the pregnancy rate. Data are presented as mean ± S.D. unless indicated otherwise. A p value of < 0.05 was considered statistically significant.

Indices:

Fertility index, gestation index, implantation index, Pre and post embryonic viability indices were observed.

Historical control data:

not specified

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Description (incidence and severity):

Erythrocyte parameters:
No significant change were observed in treated rat as compared to control.

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

In GD6, significant decrease in placental weight was observed.

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Maternal developmental toxicity

Number of abortions:

not specified

Pre- and post-implantation loss:

effects observed, treatment-related

Description (incidence and severity):

In GD0, significant increase in preimplantation loss were observed.
In GD0, GD3, GD4 and GD6, significant increase in postimplantation loss were observed as compared to control.

Total litter losses by resorption:

not specified

Early or late resorptions:

not specified

Dead fetuses:

effects observed, treatment-related

Description (incidence and severity):

Significant difference were observed in fetal mortality data for GD3 to GD6 as compare to control.

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not specified

Changes in number of pregnant:

not specified

Other effects:

not specified

Effect levels (maternal animals)

Dose descriptor:

LOAEL

Effect level:

200 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

dead fetuses

early or late resorptions

organ weights and organ / body weight ratios

pre and post implantation loss

Remarks on result:

other: Effect on reproductive performance

Maternal abnormalities

Abnormalities:

not specified

Localisation:

not specified

Description (incidence and severity):

not specified

Results (fetuses)

Fetal body weight changes:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): effects observed, treatment-related
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): Significant decreased in fetal weight were observed for male and female in GD5 and GD6

Reduction in number of live offspring:

not specified

Changes in sex ratio:

not specified

Changes in litter size and weights:

not specified

Changes in postnatal survival:

not specified

External malformations:

effects observed, treatment-related

Description (incidence and severity):

In GD6, malformation in litters and fetus were observed as compared to control.

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

In GD1 and GD2, fetus with misshapen thoracic centrum and fused ribs were observed.
In GD5, ossified sacral/caudal vertebrae were observed as compare to control.

Visceral malformations:

effects observed, treatment-related

Description (incidence and severity):

In GD5 and GD6, variations consisted of thymic remnant in the neck, persistent left unbilival artery, variation of lobation of lung; dilated ureter and dislated renal pelvis were observed as compared to control.

Other effects:

not specified

Effect levels (fetuses)

Dose descriptor:

LOAEL

Effect level:

200 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

fetal/pup body weight changes

external malformations

skeletal malformations

visceral malformations

Remarks on result:

other: Effect observed

Fetal abnormalities

Abnormalities:

not specified

Localisation:

other: not specified

Description (incidence and severity):

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Treatment related:

not specified

Relation to maternal toxicity:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

Lowest-observed-adverse-effect level (LOAEL) for P and F1 generation was considered to be 200 mg/kg/bw/day when Crj:CD (SD)IGS (SD) female rat were treated with Methyl Methansulfonate by orally by gavage for 7 days.

Executive summary:

In a developmental toxicity study, femaleCrj:CD (SD)IGS (SD)rat were treated with Methyl Methansulfonate in the concentration of 0 and 200 mg/kg/bw/day. Results show that Methyl Methansulfonate was toxic. Toxic effect was observed as reduction inNumber of live fetuses, placental weight and increased preimplantation loss and postimplantation loss in treated rat as compared to control. In addition gross pathological changes such as malformation of litters and fetus, external malformations in live fetuses and ossified sacral/caudal vertebrae were observed. Therefore,lowest-observed-adverse-effect level (LOAEL) for P and F1 generation was considered to be 200 mg/kg/bw/day when Crj:CD (SD)IGS (SD) female rat were treated with Methyl Methansulfonate by orally by gavage for 7 days.