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Toxicological information

Toxicity to reproduction

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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:
other: according to information in OECD SIDS (2002)
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Identity: Tris(2-hydroxyethyl) isocyanurate (CAS: 839-90-7)
- Source: Nissan Chemical Industries, Ltd.; Lot No. 00915-1
- Purity: 99.0 %

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
PARENTAL TEST ANIMALS
- Age at study initiation: 10 weeks old, both sexes
- Weight at study initiation: 335-364 g for males, 233-263 g for females

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
for injection
Details on exposure:
Treatment of parental animals by oral gavage administration. Test substance was not directly administered to F1 animals, as these pubs were sacrificed on day 4 post partum, i.e. day 4 of lactation.
Details on mating procedure:
- Male/female ratio per cage: 1/1
- Length of cohabitation: At the most 14 days, until proof of pregnancy was confirmed. 
- Proof of pregnancy: Formation of vaginal plug or sperm in vaginal smear referred to as day 0 of pregnancy.
(During cohabitation, females were checked every morning for pregnancy)

Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
- Treatment period, Parental males: 49 days (14 days before mating and 35 days including 14 days for mating)
Treatment period, Parental females: 40-46 days (from 14 days prior to mating to day 3 of lactation.)
- Frequency of treatment: Daily
- Post treatment observation period: 1 day
- Duration of test, Parental males: 50 days
Duration of test, Parental females: From 14 days prior to mating to day 4 of lactation.
Duration of test, Pups: Until day 4 of lactation.

Frequency of treatment:
Daily
Details on study schedule:
- Age at mating of the mated animals in the study: 12 to 14 weeks
Doses / concentrationsopen allclose all
Dose / conc.:
30 mg/kg bw/day (actual dose received)
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Dose / conc.:
300 mg/kg bw/day (actual dose received)
Dose / conc.:
1 000 mg/kg bw/day (actual dose received)
No. of animals per sex per dose:
12
Control animals:
yes, concurrent vehicle

Examinations

Parental animals: Observations and examinations:
Clinical observations performed and frequency:
- Clinical signs: Twice a day (just before and after administration)
- Body weight, Males: Twice a week
Body weight, Females: Twice a week for pre-mating and mating period, 0, 7, 14, 21st day of pregnancy and 0, 4th day of lactation period.
- Food consumption, Males: Twice a week for pre-mating period and after a mating period end.
Food consumption, Females: Twice a week for pre-mating period, 2, 9, 16, 21st day of pregnancy and 4th day of lactation period.
- Hematology, Blood Chemistry, Urinalysis in parental males only. *

* Detailed in separate endpoint study record, i.e. "7.5.1 Repeated dose toxicity: oral - MHLW Repeat dose tox.: oral, rat, 2001"
Oestrous cyclicity (parental animals):
Frequency of vaginal estrus was determined from the beginning of the treatment period to the day of confirmed copulation.
Sperm parameters (parental animals):
Parameters examined in male parental animals: testis weight, epididymis weight
Litter observations:
STANDARDISATION OF LITTERS: Not performed. The study ended on day 4 post partum.

LITTER PARAMETERS EXAMINED
- No. of pregnant females with live pups on day 0.
- Gestation index (No. of females with live pups/No. of living pregnant females x 100)
- No. of pregnant females with live pups on day 4
- Delivery index  (No. of pups born/No. of implantation sites x 100)
- No. of pups alive on day 0 of lactation,
- Live birth index (No. of live pups on day 0/No. of pups born x 100)
- Sex ratio  (Total No. of male pups/Total No. of female pups)
- No. of pups alive on day 4 of lactation
- Viability index (No. of live pups on day 4/No. of live pups on day 0 x 100)
- Clinical signs, twice a day after birth
- Body weight of live pups (on day 0 and 4).



Postmortem examinations (parental animals):
GROSS PATHOLOGY: Yes, see below
WEIGHING OF ORGANS: Yes, see below
HISTOPATHOLOGY: Yes, see below

- Terminal sacrifice, Males: Killed on the day after the treatment period.
Terminal sacrifice, Females: Killed on day 4 of lactation. Females with no delivery were killed 4 days after the delivery expected date.
Females with no copulation were killed at the end of the mating period.

- Gross pathology: All rats received a full macroscopic examination  with tissue collection.

- Organs Weights: The following organs were weighed at necropsy:
Brain, pituitary, thyroids, heart, thymus, liver, spleen, adrenals, kidneys, testes, epididymides, ovaries.

- Histopathology: The following organs were microscopically observed for the control and 1000 mg/kg bw/day groups:
Brain, pituitary gland, thyroids, heart, thymus, liver, spleen, adrenals, kidneys, testes, epididymides, ovaries,
lung, trachea, pancreas, salivary glands, esophagus, stomach, duodenum, jejunum, ileum, caecum, rectum,
colon, lymph node, bladder, uterus, vagina, parathyroids, spinal cord, sciatic nerve, eyes, Harderian glands,
mammary gland,  bone marrow, seminal vesicle, prostate.
In addition, liver and spleen (male only) were also examined for the 30, 100 and 300 mg/kg bw/day groups.

Postmortem examinations (offspring):
Full macroscopic examination of all pups
Statistics:
Dunnett's test was used for numerical data. Chi square test was used for copulation index and fertility index analysis.
Reproductive indices:
- No. of pairs with successful copulation
- Copulation index (No. of pairs with successful copulation/No. of pairs mated x 100)
- Pairing days until copulation
- No. of pregnant females
- Fertility index (No. of pregnant animals/No. of pairs with successful copulation x 100)
- No. of corpora lutea
- No. of implantation sites
- Implantation index (No. of implantation sites/No. of corpora lutea x 100)
- No. of living pregnant females
- No. of pregnant females with parturition
- Gestation length
- For further reproductive parameters, see also the above section "Litter observations"
Offspring viability indices:
- Viability index (No. of live pups on day 4/No. of live pups on day 0 x 100).
- For further parameters indicative of the viability of the offspring, see also the above section "Litter observations"

Results and discussion

Results: P0 (first parental animals)

General toxicity (P0)

Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
only in 2 females, no effect in males
Other effects:
not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed

Details on results (P0)

Mortality:
- No deaths occurred in all dams during the study.

Histopathology:
- Males:  No treatment-related abnormality was observed.
- Females:  Very slight (marginally positive) extramedullary hematopoiesis in the liver was noted in two female animals of the 1000 mg/kg bw/day gro up.

Other Examinations (addressed in separate endpoint study record "7.5.1 Repeated dose toxicity: oral - MHLW Repeat dose tox.: oral, rat, 2001"):
- Hematological examinations (only for males)
- Blood chemical examinations (only for males)
- Urinary examinations (only for males)

Effect levels (P0)

open allclose all
Key result
Dose descriptor:
NOEL
Effect level:
1 000 mg/kg bw/day
Sex:
male
Basis for effect level:
other: NOEL = highest dose tested. NOEL (instead of NOAEL stated by OECD SIDS) seems more appropriate, because OECD SIDS states: "No treatment related abnormality up to 1000 mg/kg bw/day in parental males."
Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Sex:
female
Basis for effect level:
other: NOAEL = highest dose tested. Very slight extramedullary hematopoiesis in the liver in two parental females at 1000 mg/kg bw/day was statistically not significant, therefore not adverse.

Target system / organ toxicity (P0)

Key result
Critical effects observed:
no

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Histopathological findings:
not examined

Details on results (F1)

No treatment-related abnormality was observed.

ADDITIONAL FETAL DATA:

No abnormality in sex ratio.

Grossly Visible Abnormalities and External Abnormalities:
Proboscis was observed in a stillbirth pup at 300 mg/kg bw/day. No treatment related external abnormality was observed among newborns.

Effect levels (F1)

Key result
Dose descriptor:
NOEL
Generation:
F1
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
dams were dosed
Sex:
male/female
Basis for effect level:
other: NOEL = highest dose tested. NOEL (instead of NOAEL stated by OECD SIDS) seems more appropriate, because OECD SIDS states: "No abnormalities in all indexes obtained from pups in each dose group."

Target system / organ toxicity (F1)

Key result
Critical effects observed:
no

Overall reproductive toxicity

Key result
Reproductive effects observed:
no

Any other information on results incl. tables

There were no statistically significant differences from concurrent controls.

Applicant's summary and conclusion

Conclusions:
There were no treatment related abnormalities. The no observed adverse effect level (NOAEL) for maternal toxicity and the no observed effect level (NOEL) for foetal toxicity are 1000 mg/kg bw/day.