Tetrahydrothiophene 1,1-dioxide

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

not specified

Principles of method if other than guideline:

No further information available.

GLP compliance:

yes

Remarks:

, but not stated in report.

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tetrahydrothiophene 1,1-dioxide

EC Number:

204-783-1

EC Name:

Tetrahydrothiophene 1,1-dioxide

Cas Number:

126-33-0

Molecular formula:

C4H8O2S

IUPAC Name:

1λ⁶-thiolane-1,1-dione

Constituent 2

Reference substance name:

Sulfolane

IUPAC Name:

Sulfolane

Constituent 3

Reference substance name:

Tetrahydrothiophene-1,1-dioxide

IUPAC Name:

Tetrahydrothiophene-1,1-dioxide

Details on test material:

- Name of test material (as cited in study report):Tetrahydrothiophene-1,1-dioxide
- Physical state: clear liquid at room temperature
- Analytical purity: 97.3%
- Lot No.: 20802
- Stored under room temperature

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Source: Charles River Laboratories, Japan
- Age at study initiation: 10 weeks
- Weight at study initiation: Males 355-379 g, females 209-228 g
- Housing: Individually in stainless steel cages. Each dam was moved to a plastic cage with a mat 18 days after pregnancy.
- Diet: CRF-1 (Oriental Yeast Co., LTD) ad libitum
- Water: Tap water ad libitum.
- Acclimation period: Approximately 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 20-26°C
- Humidity: 40-70%
- Air changes: 12 times per hour.
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: Not reported.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTION
The test material was diluted with injection water to prepare a test solution. A dose was indicated by the weight of the test compound made available (after purity adjustment). The test solution was stored at room temperature under light-shielded conditions and used within 7 days after preparation, since the solution had been confirmed to cause no problems in stability when stored for 7 days under these conditions. The test compound content in the test solution of each concentration used on the starting day and on the final day of dosing of male rats was confirmed to indicate that there was no problem with the test compound concentration. The sample solution was adjusted so that the amount of 5 mL/kg body weight may be administered.

Details on mating procedure:

- M/F ratio per cage: 1 male and 1 female
- Length of cohabitation: until evidence of mating seen or for 2 weeks
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged Individually

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

No information given in report.

Duration of treatment / exposure:

Two weeks prior to mating, during mating, and continuing through day 19 of gestation. The dams were then allowed to deliver their litters, which were retained until lactation day 4.

Frequency of treatment:

Daily

Details on study schedule:

No information is available.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

60 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

200 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

700 mg/kg bw/day (nominal)

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

The dose selection was based on the findings of the 28-day oral toxicity study, in which decreased body weight and food consumption was seen in the 700 mg/kg-day group.

Positive control:

None

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least twice/day

BODY WEIGHT: Yes
- Time schedule: Females day treatment initiated, twice/week until copulation confirmed, gestation days 0, 7, 14 and 21, lactation days 0 and 4. Females without evidence of mating were weighed weekly. All weighed at termination. Males: twice/week

FOOD CONSUMPTION: Yes
- Time schedule: Females twice/weekly during pre-mating period, gestation days 2, 9, 16, and 21and on lactation day 4.

Oestrous cyclicity (parental animals):

Once a day during pre-mating period until the day of copulation confirmed. Estrus occurring on two consecutive days was counted as one cycle.

Sperm parameters (parental animals):

Not determined

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: No

PARAMETERS EXAMINED
The following parameters were examined as soon as possible after parturition and twice / day thereafter: number of live and dead pups and sex of pups, physical or behavioural abnormalities.

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities.

Postmortem examinations (parental animals):

SACRIFICE
- Maternal animals: Mated animals on day 5 post partum, animals when evidence of mating was detected but failed to deliver 25 days after evidence of mating, animals with no evidence of mating after completion of mating period. Male animals: At the end of 49 days of treatment.

GROSS NECROPSY
- Number of implantation sites and corpora lutea were assessed.

ORGAN WEIGHTS
- Maternal animals: ovaries. Male animals: testes and epididymis.

MICROSCOPIC EXAMINATION: Yes
- Maternal animals: ovaries. Male animals: testes and epididymis. Only the control and 700 mg/kg group organs were examined.

Postmortem examinations (offspring):

External macroscopic postmortem examinations performed on all F1 pups found dead during lactation and at termination on lactation day 4. No microscopic examination of pups.

Statistics:

A homoscedasticity test according to the Bartlett method was carried out for the statistical analysis. When homoscedastic, a dispersion analysis was carried out using the one-way layout method. If the results were significant, the Dunnett method was applied. If not deemed to be homoscedastic, the one-way layout analysis utilizing the order (Kruskal-Wallis test) was carried out. If the results were found significant, the Dunnett-type test utilizing the order was applied. The copulation index, fertility index, and birth index were identified by the chi-square test.

Reproductive indices:

Gonadal function, mating behavior, implantation, and general fertility were evaluated.

Offspring viability indices:

Litter size, pup survival, sex, body weight, and the presence of gross external malformations were assessed in the offspring.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

effects observed, treatment-related

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
Males: Soiled fur, diarrhea, and soft stool were observed in the 700 mg/kg group. One male rat died in the 700 mg/kg group on day 5 of administration.
Females: Soiled fur and hypersalivation were observed in the 700 mg/kg group. One female rat died in the 700 mg/kg group on lactactional day 2.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Males: Significantly reduced body weights on days 4 until study termination in the 700 mg/kg group compared to controls. In the 200 mg/kg group, body weight was significantly decreased on day 4, but were similar to controls thereafter. Significantly lower food consumption was seen on days 3 and 6 in the 700 mg/kg group, but not thereafter. In the 200 mg/kg group, there was a significant on day 3 only.
Females: Significantly lower body weights in the 700 mg/kg group on days 4-11 of the pre-mating period. No significant differences in body weights between treated and control dams during the gestation and lactation periods. Significantly lower food consumption in the 700 mg/kg group on days 3 and 6 of the pre-mating period. No significant differences between treated and control dams during the pregnancy periods; there was, however, reduced in the 700 mg/kg dams on lactation day 4 compared to the controls.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
High-dose females exhibited significantly reduced number of estrous cycles during pre-mating period compared to controls (2.2 + 0.9 and 3.3 + 0.5, respectively). Four female rats were reported to exhibit irregular estrous cycles.

ORGAN WEIGHTS (PARENTAL ANIMALS)
Relative (to body weight) ovarian weights were significantly higher in the 700 mg/kg dams.

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Remarks:

reproductive toxicity

Effect level:

200 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: complete litter loss in four dams during lactation period at 700 mg/kg/bw/day.

2

Key result

Dose descriptor:

NOAEL

Remarks:

(systemic toxicity)

Effect level:

200 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

body weight and weight gain

Target system / organ toxicity (P0)

Critical effects observed:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not specified

Details on results (F1)

VIABILITY (OFFSPRING)
The birth index (# of live pups born/# of implantation scars x 100) was significantly decreased in the 200 and 700 mg/kg dose groups compared to controls. The number of dead pups on lactation day 0, the live birth index, the number of live pups on lactation day 4, and the viability index were significantly reduced in the 700 mg/kg dose groups. Four dams in the 700 mg/kg dose group lost all of their newborn pups during the lactation period.

There was also a statistically significant decrease in delivery index (# of live pups born/# of implantation scars x 100) in the 200 mg/kg dose group.

BODY WEIGHT (OFFSPRING)
At 700 mg/kg, body weights were significantly reduced in both male and female pups on both lactation days 0 and 4. There was also a significantly significant decrease in male pup weights in the 60 mg/kg group on lactation day 0; this was considered to be spurious and not treatment-related.

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Remarks:

Developmental toxicity

Generation:

F1

Effect level:

60 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: reduced birth index at 200 mg/kg/bw/day

Target system / organ toxicity (F1)

Critical effects observed:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Provide table on delivery index, birth index, dead pups on LD 0, live birth index, live pups on LD 4. Add a second table with pup body weights on LD 0 and 4.

Applicant's summary and conclusion

Conclusions:

Under conditions of this test, sulfolane did not influence fertility or reproductive performance. Sulfolane did, however, affect pre- and postnatal development at 200 and 700 mg/kg/day.

Executive summary:

Crj: CD(SD) rats were dosed by oral gavage with 0, 60, 200 and 700 mg/kg sulfolane. Males were dosed for 49 days (14 days pre-mating, mating and post mating). Females were dosed for 14 days pre-mating, mating, gestation, and until day 4 after delivery. In the 700 mg/kg group, body weights were significantly lower in males on days 4-49 and in females on days 4-11 (pre-mating period). There were no significant differences in body weights between treated and control dams during the gestation and lactation periods. Food consumption was not generally affected in males and females, although food consumption was significantly reduced in the high-dose females on lactation day 4. 

There were no treatment-related effects on fertility or parameters of reproductive performance. High-dose females, however, exhibited significantly reduced number of estrous cycles during pre-mating period compared to controls. At study termination, relative (to body weight) ovarian weights were significantly higher in the 700 mg/kg dams. The birth index was significantly decreased in the 200 and 700 mg/kg dose groups compared to controls. The number of dead pups on lactation day 0, the live birth index, the number of live pups on lactation day 4, and the viability index were significantly reduced in the 700 mg/kg dose groups. Four dams in the 700 mg/kg dose group lost all of their newborn pups during the lactation period. There was also a statistically significant decrease in delivery index in the 200 mg/kg dose group. At 700 mg/kg, body weights were significantly reduced in both male and female pups on both lactation days 0 and 4. There was also a significantly significant decrease in male pup weights in the 60 mg/kg group on lactation day 0; this was considered to be spurious and not treatment-related. The NOAEL for parental toxicity was considered to be 200 mg/kg-day. The NOAELs for reproductive and developmental toxicity were 200 and 60 mg/kg-day, respectively.