Registration Dossier

Toxicological information

Toxicity to reproduction

Currently viewing:

Administrative data

Endpoint:
two-generation reproductive toxicity
Remarks:
based on test type (migrated information)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
October 2002 - June 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed under GLP and according to standard protocol.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Sodium Chlorate
- Molecular weight (if other than submission substance): 106.45
- Physical state: at receipt: yellow/orange granulates; on analytical certificate: whitish solid
- Analytical purity: 99.68%
- Composition of test material, percentage of components: NaClO3 = 99.68%, H2O = 0.022%, NaCl = 0.017%, Ca3(PO4)2 = 0.12%, Fe2O3 = 0.16% (performed by Atofina). CoA is attached to the report (last pages).
- Purity test date: October 3, 2002
- Lot/batch No.: 1E012 1 UM
- Expiration date of the lot/batch: October 2003
- Stability under test conditions: no info
- Storage condition of test material: in dark (protected from light) and at room temperature
- Other: received on 30 November 2001 from ATOFINA; Container : one metallic pot; Melting point = 248ºC; Solubility = soluble in water (20ºC)

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, L'Arbresle, France
- Age at study initiation: (P) 6 wks; (F1) 3 wks
- Weight at study initiation: (P) Males: 189 g (176-205g); Females: 153 g (138-170g); (F1) only detailed info
- Fasting period before study: no because of repeated exposure
- Housing: P animals were housed individually in wire mesh cages; prior to delivery and during lactation P and F1 females were housed individually in polycarbonate cages; after weaning the F1 animals were housed individually in wire-mesh cages
- Use of restrainers for preventing ingestion (if dermal): not applicable
- Diet (e.g. ad libitum): free access to A04 C pelleted maintenance diet
- Water (e.g. ad libitum): free access to tap water
- Acclimation period: 6-day acclimation period


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 50 ± 20
- Air changes (per hr): about 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12h/12h (7:00 - 19:00)


IN-LIFE DATES: From: October 28, 2002 To: June 30, 2003

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: The test item was administered as a solution in the vehicle (concentrations of 2, 14 and 100 mg/mL). The test item dosage forms were prepared by the Pharmacy at weekly intervals and stored at +4°C, away from light prior to use.

VEHICLE
- Justification for use and choice of vehicle (if other than water): purified water
- Concentration in vehicle: 2, 14 and 100 mg/mL
- Amount of vehicle (if gavage): (The quantity of the dosage form administered to each animal was adjusted according to the most recently recorded body weight). A constant dosage-volume of 5 mL/kg/day was used.
- Lot/batch no. (if required): not required
- Purity: purified water
Details on mating procedure:
- M/F ratio per cage: 1
- Length of cohabitation: during mating: each female was placed with the same male until mating occurred or 14 days had elapsed
- Proof of pregnancy: vaginal plug and sperm in vaginal smear; referred to as day 0 of pregnancy
- After ... days of unsuccessful pairing replacement of first male by another male with proven fertility. No info.
- Further matings after two unsuccessful attempts: no info
- After successful mating each pregnant female was caged (how): Each pair was separated and by the end of pregnancy, the females were individually placed in appropiate cages with nesting material.
- Any other deviations from standard protocol: no
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- Stability and Concentration are examined, Homogenicity isn't determined. For stability and concentration no acceptability criteria are given in the method section. In the result section criteria are given (±10%), however 2 of the samples differ more than 10%, so that's remarkable.
- Stability: A previous study using the same batch (CIT/ Study No. 22823RSR) demonstrated the satisfactory stability of dosage forms (range 8-200 mg/mL) over a 9-day period at, room temperature, protected from light. In the present study, the stability of the low concentration was checked.
A dosage form at 2 mg/mL was prepared, protected from light then sampled after 0 (just after preparation) and 9 days storage at +4°C. All samples were analyzed as soon as possible after sampling. The mean result of two determinations (day 0) was taken as the initial value for the stability test.
- Concentration: The concentration of samples taken from each dosage form (including the control) prepared for use in weeks 1, 6, 12, 19, 24, 30 and 35 was determined.
Duration of treatment / exposure:
Exposure period: see "details on study schedule"
Premating exposure period (males): 10 weeks
Premating exposure period (females): 10 weeks
Duration of test: 2 generations
Frequency of treatment:
daily
Details on study schedule:
- Number of generation studies: 2
- Detailed description of duration treatment / exposure:
F0 generation
. 10 weeks before mating, during the mating period until sacrifice (weaning of pups) for the males.
. 10 weeks before mating, during the mating, pregnancy and lactation periods (until day 21 post-partum) for the females.
F1 generation
At weaning of the F1 generation, on day 22 post-partum, three groups of 25 male and 25 female Sprague-Dawley rats received the test item under the same experimental conditions as above, during their growth, adulthood, mating, pregnancy and lactation, until weaning of the F2 generation.

- F1 parental animals not mated until they are 12 to 14 weeks old (9-11 weeks after selected from the F1 litters).
- Selection of parents from F1 generation when pups were 22 days post-partum of age.
- Age at mating of the mated animals in the study: 12 to 14 weeks
Doses / concentrations
Remarks:
Doses / Concentrations:
10, 70 or 500 mg/kg/day
Basis:
nominal conc.
No. of animals per sex per dose:
25
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: the dose-levels were specified by the Sponsor and were selected on the basis of a previous 1-generation dose-range finding study in rats (CIT/Study No. 22823 RSR; dose-levels of 40, 200 and 1000 mg/kg/day).
- Rationale for animal assignment (if not random): animals were allocated to the groups (by sex), according to a computerized stratification procedure, so that the average body weight of each group was similar.
Positive control:
Not required.

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS + DETAILED CLINICAL OBSERVATIONS + BODY WEIGHT + FOOD CONSUMPTION AND COMPOUND INTAKE + WATER CONSUMPTION AND COMPOUND INTAKE
Clinical signs and mortality were checked daily. Food consumption and body weight were recorded at designated intervals. During lactation, the pups (F1 generation) were observed daily for survival and clinical signs; body weight was recorded at designated intervals; the sex-ratio was recorded. On day 22 post-partum, one male and one female pup per litter were selected to constitute the F1 generation, which comprised 25 males and 25 females per group. The F1 animals were observed daily for clinical signs and mortality. Body weight and food consumption were recorded once a week. Sexual development of both males and females was assessed. Neurobehavioural tests were conducted at designated intervals to assess auditory and visual functions. Spontaneous locomotor activity was also evaluated over a 10-min interval when the animals were between 7 and 8 weeks. During lactation, the pups (F2 generation) were observed daily for survival and clinical signs; body weight was recorded at designated intervals; the sex-ratio was recorded.
Oestrous cyclicity (parental animals):
- Estrous cycle: The estrous cycle stage was determined was evaluated in both F0 and F1 females from a fresh vaginal lavage (stained with methylene blue), each morning as follows:
. during the last three weeks of the pre-mating period,
. during the mating period, until the females were mated.
Sperm parameters (parental animals):
- Sperm examination: Epididymal and testicular sperm parameters were evaluated in both F0 and F1 males. Before sacrifice, each male was kept under isoflurane anesthesia, the left epididymide was sampled, weighed and sperm was collected from the cauda for investigation.
Litter observations:
STANDARDISATION OF LITTERS
On day 4 post-partum, the size of each F1 litter was adjusted to obtain eight pups per litter (four males and four females).


PARAMETERS EXAMINED
See above 'Parental animals: observations and examinations'
Postmortem examinations (parental animals):
SACRIFICE + GROSS NECROPSY + HISTOPATHOLOGY / ORGAN WEIGHTS
A macroscopic post-mortem examination was performed on all F0 and F1 parent males and females and on three pups per sex and per litter of each F0 and F1 females killed at weaning. Any pups which died during the lactation period or were not selected were also submitted to macroscopic post-mortem examination. Macroscopic lesions, reproductive organs, adrenals, thyroids and pituitary glands were sampled in all parent animals. In all pups, the macroscopic lesions, the thyroid and pituitary glands were also preserved. A microscopic examination was performed on macroscopic lesions, reproductive organs, adrenals, and pituitary glands of all F0 and F1 parents of the control and high dose groups and on the thyroid gland for all F0 and F1 parents. Particular detailed histopathological examinations were performed for the ovaries and the testes. A microscopic examination of the thyroid gland was also performed for all pups of the F2 generation
- Organ weights P and F1: Designated organs were weighed for F0 and F1 parents as well as brain, spleen, thymus and thyroids of one pup per sex per litter of each generation.
- Histopathology P and F1: see above
- Histopathology F1 not selected for mating, F2: see above

OTHER EXAMINATIONS
After weaning of their respective progeny, F0 and F1 parent males and females were sacrificed. Blood was sampled for determination of hematology parameters in F0 males and F0 females only.
Postmortem examinations (offspring):
See above 'Postmortem examinations (Parental animals)'
Statistics:
Data other than organ weights: Mean values were compared by one-way analysis of variance and Dunnett test (mean values being considered as normally distributed and variances being considered as homogeneous). Percentage values were compared by the Fisher exact probability test.

For statistical methods used for organ weights: see appended table.

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:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Other effects:
not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
effects observed, treatment-related

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
Description, severity, time of onset and duration of clinical signs: Parents: No effects. However, at 500 mg/kg/day, ptyalism was recorded in 1 male and a few other clinical signs were randomly distributed among the treated groups (1 or 2 males per group). According to females there were no relevant signs of toxicity in any group. In conclusion: All these signs were not considered to be of toxicological significance.
Mortality P: There was no death in any group during the whole study period.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
BW Parents: No effects.
Food Parents: No effects.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
-

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
Changes in estrous cycles: The estrous cycle stages evaluated during the last three weeks of the premating period were not affected by the treatment.

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
Effects on sperm in P and F1: The seminology parameters evaluated in both P and F1 males, namely epididymal sperm count, epididymal sperm motility and morphology, testicular sperm head count and daily sperm production were not affected by the treatment at any dose-level.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
In P and F1:
- Reproductive parameters in females with evidence of mating:
P
Dose mg/kg/day 0 10 70 500
Paired animals 25M+25F 25M+25F 25M+25F 25M+25F
evidence of mating 24(25) 24(25) 22 (24)25
Mating index (%) 96(100) 96(100) 88(96) 100
Pre-coital interval(d) 2.96 2.88 3.09 2.44
Fertility index (%) 96(96) 100(100) 95(96) 96
Females which delivered 23 24 21 24
Gestation index (%) 100 100 100 100
Gestation length (days) 21.5 21.4 21.3 21.4
Post-implantation + 6.5 7.4 7.9 5.8
neo-natal losses (%)
M: male, F: female, (): pregnant females with no evidence of mating are taken into account.

- Reproductive parameters in females with evidence of mating:
F1
Dose mg/kg/day 0 10 70 500
Paired animals 25M+25F 25M+25F 25M+25F 24M+24F
evidence of mating 25 24 22(23) 23(24)
Mating index (%) 100 96 88(92) 96(100)
Pre-coital interval (d) 3.28 3.29 2.23 2.70
Fertility index (%) 92 96 91(91) 96(96)
Pregnant mated females 23 23 20(21) 22(23)
Females which delivered 23 23 20 22
Gestation index (%) 100 100 100 100
Gestation length (days) 21.6 21.6 21.5 21.6
Post-implantation + 3.7 10.7 5.7 9.2
neo-natal losses (%)
M: male, F: female, (): pregnant females with no evidence of mating are taken into account.

- Ovarian primordial follicle counts and growing follicles:
P:
Dose mg/kg/day 0 500
Primordial follicle
Total number 477 755
Mean Value 19.08 30.20
Range 0-44 5-94
Growing Follicles
Total number 66 39
Mean Value 2.64 1.56
Range 0-9 0-6
F1:
Primordial follicle
Total number 457 538
Mean Value 18.28 21.52
Range 7-49 5-47
Growing Follicles
Total number 43 27
Mean Value 1.72 1.08
Range 0-5 0-5

A relationship to the treatment was considered to be unlikely. Considering the great variability described in published literature for such quantitative analysis and when the quantitative parameters were evaluated, as per defined intervals of values it appeared more evident that the differences observed were due, at least in part, to the great inter-individual variability.
ORGAN WEIGHTS (PARENTAL ANIMALS)
Organ weight changes P, F1 and F2:
An increased spleen weight was observed in 500 mg/kg day P and F1 males. It was considered that the differences in spleen weight were most probably secondary to the anaemia noted among the animals and consequently of no toxicological importance. Other differences in organ weights in P, F1 and F2 were not dose-related and/or without the same trend in both sexes. As the differences in thyroid and thymus weight were minimal and not dose-related, they were considered to be of no toxicological importance.

GROSS PATHOLOGY (PARENTAL ANIMALS)
Gross pathology incidence and severity:
The only macroscopic findings observed were those which have been found to occur spontaneously in the untreated laboratory rat of this strain and age. They were therefore considered to be of no toxicological importance.

HISTOPATHOLOGY (PARENTAL ANIMALS)
- Histopathology incidence and severity, P, F1 and F2:
Parents:
At 500 mg/kg/day minimal to moderate follicular thyroidal hyperplasia and moderate hyperactivity of the thyroids in both parent males and females. At 70 mg/kg/day moderate follicular hyperactivity of the thyroids in the parents.

P:
Follicular thyroidal hyperplasia:
Dose-level (mg/kg/day) 0 10 70 500
Males Incidence 0/25 0/25 0/24 20/24
Grade 1 - - - 0
Grade 2 - - - 18
Grade 3 - - - 2
Mean grading - - - 2.1

Females Incidence 0/25 0/25 0/25 18/25
Grade 1 - - - 7
Grade 2 - - - 8
Grade 3 - - - 3
Mean grading - - - 1.8

Follicular thyroidal hyperactivity:
Dose-level (mg/kg/day) 0 10 70 500
Males Incidence 25/25 25/25 24/24 24/24
Grade 2 11 3 3 2
Grade 3 12 20 15 15
Grade 4 2 2 6 7
Mean grading 2.6 3.0 3.1 3.2

Females Incidence 24/25 25/25 25/25 25/25
Grade 2 16 8 8 3
Grade 3 8 16 17 16
Grade 4 0 1 0 6
Mean grading 2.3 2.7 2.7 3.1

F1:
Follicular thyroidal hyperplasia:
Dose-level (mg/kg/day) 0 10 70 500
Males Incidence 0/25 0/25 0/24 21/22
Grade 1 - - - 3
Grade 2 - - - 12
Grade 3 - - - 6
Mean grading - - - 2.1

Females Incidence 0/25 0/25 0/25 20/25
Grade 1 - - - 6
Grade 2 - - - 10
Grade 3 - - - 4
Mean grading - - - 1.9

Follicular thyroidal hyperactivity:
Dose-level (mg/kg/day) 0 10 70 500
Males Incidence 25/25 25/25 24/24 22/22
Grade 1 2 0 0 0
Grade 2 6 4 6 3
Grade 3 17 21 15 16
Grade 4 0 0 3 3
Mean grading 2.6 2.8 2.9 3.0

Females Incidence 25/25 25/25 24/25 24/25
Grade 1 2 1 1 0
Grade 2 12 13 12 5
Grade 3 11 11 11 16
Grade 4 0 0 0 3
Mean grading 2.4 2.4 2.4 2.9

F2:
Dose mg/kg/day Microscopic findings 0 10 70 500
Males Follicular cell hypertrophy 91 97 100 100
1.3 1.3 1.2 1.2
Small follicles 91 97 100 100
1.5 2.1 1.8 2.4
Pale or decreased colloid contents 91 95 100 100
1.2 2.0 1.7 2.3
Cords of epithelial cells 66 84 98 90
1.4 1.5 1.3 1.7
Females Follicular cell hypertrophy 100 98 98 100
1.0 1.0 1.1 1.0
Small follicles 100 98 98 100
1.9 2.0 1.9 2.4
Pale or decreased colloid contents 100 98 98 100
1.8 2.0 1.8 2.4
Cords of epithelial cells 88 95 95 95
1.3 1.7 1.7 1.8

There was an absence of characterized thyroidal hypertrophy at all dose-levels and in both sexes. The cords of epithelial cells with small follicles and decreased or pale colloid contents are morphological characteristics of an infant thyroidal tissue. As they were recorded without evidence of a dose or treatment relationship, it was concluded that the small morphological differences observed between treated and control F2 pups were without relationship to treatment with the test item and correlated with the morphological characteristics of an infant thyroidal tissue.

The only other microscopic findings were those which are commonly encountered in the untreated laboratory rat of this strain and age and were thus considered to be without relationship to treatment with the test item.

OTHER FINDINGS (PARENTAL ANIMALS)
- LACTATION:
Changes in lactation:
P
Dose mg/kg/day 0 10 70 500
lactation index (%) 100.0 98.9 99.4 97.4
CIT Historical Control Data for lactation index on day 21 pp: minimum = 96.4, maximum = 100%
The lactation index was in the range of historical control data.

- HEMATOLOGICAL FINDINGS
Hematological findings incidence and severity: Parents: At 500 mg/kg/day significant decrease in red blood cell count and mean hemoglobin concentration in both parental males and females.
Dose-level (mg/kg/day) 0 10 70 500
Males
RBC (T/L) 8.76 8.73 8.61 8.02**
HB (g/dL) 15.7 15.8 15.3 14.5**
PCV (L/L) 0.45 0.46 0.44 0.43**
MCHC (g/dL) 34.7 34.5 34.7 33.9**
Females
RBC (T/L) 7.62 7.57 7.29* 6.98**
HB (g/dL) 15.6 15.5 15.1* 14.7**
PCV (L/L) 0.45 0.45 0.44 0.43*
MCHC (g/dL) 34.7 34.5 34.5 34.1**
Statistically significant: * p <0.05, ** p <0.01

CIT historical control data:
Males
RBC (T/L) : mean = 8.64, minimum = 7.56, maximum = 9.56
HB (g/dL) : mean = 15.3, minimum = 13.8, maximum = 16.6
PCV (L/L) : mean = 0.45, minimum = 0.40, maximum = 0.49
MCHC (g/dL) : mean = 33.9, minimum = 32.4, maximum = 34.9
Females
RBC (T/L) : mean = 7.60, minimum = 6.53, maximum = 8.33
HB (g/dL) : mean = 14.3, minimum = 13.1, maximum = 15.5
PCV (L/L) : mean = 0.42, minimum = 0.37, maximum = 0.46
MCHC (g/dL) : mean = 34.3, minimum = 32.8, maximum = 35.7

Effect levels (P0)

open allclose all
Dose descriptor:
NOAEL
Effect level:
70 mg/kg bw/day
Sex:
male/female
Dose descriptor:
NOEL
Remarks:
Parental tox M
Effect level:
10 mg/kg bw/day
Sex:
male
Dose descriptor:
NOEL
Remarks:
Parental tox F
Effect level:
70 mg/kg bw/day
Sex:
female
Dose descriptor:
NOEL
Remarks:
for mating behaviour, fertility and gestation, of each generation and for development, growth and survival of each progeny
Effect level:
500 mg/kg bw/day
Sex:
male/female
Remarks on result:
other: Generation: all (migrated information)

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Sexual maturation:
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings:
effects observed, treatment-related

Details on results (F1)

VIABILITY (OFFSPRING)
Mortality F1:
. There was no death in the control or the 10 mg/kg/day group during the whole treatment period.

. In the 70 mg/kg bw/day group 2 males died, on day 95 and day 98. In the first male a prematurely sacrificed on day 98 of the treatment period for humane reasons. Post-mortem macroscopic examination, noted a perforation in the cervical region of esophagus with a pouch, and found in adjacent tissue, measuring 2.5 cm in diameter and showing thick whitish contents at cut surface. At microscopic examination, there was a para-esophageal abscess and marked granulation tissue formation including the cervical skeletal muscles. In the second male no signs for cause of death could be determined.

. In the 500 mg/kg bw/day group 3 males died, on day 69, 96 and day 98.
- For the male found dead on day 98 of the treatment period:
At macroscopic post-mortem examination, perforation was noted in the cervical region of esophagus with a pouch, found in adjacent tissue, measuring 2.5 cm in diameter and showing thick whitish contents at cut surface. At microscopic examination, there was a para-esophageal abscess and marked granulation tissue formation including the cervical skeletal muscles. The major factor contributing to the death was esophagus perforation.
- For the male found dead on day 96 of the treatment period:
At macroscopic post-mortem examination, foamy contents were seen in the trachea and bronchi and the lungs and heart were blackish in color. Except for congestion, most probably passive, due to the absence of bleeding, no relevant microscopic finding was noted.
- For the male found dead on day 69 of the treatment period:
At macroscopic post-mortem examination, liquid whitish contents were noted in the thoracic cavity. In addition, moderate cortical cell hypertrophy was noted in the adrenals, associated with moderate lipid depletion. This was most probably related to the poor physical condition of this animal before death. No other relevant microscopic finding was noted.

During the premating period, one female given 500 mg/kg/day was found dead after dosing on day 41, no clinical signs were noted prior to death. At necropsy, foamy contents were seen in the trachea and the lungs which were reddish in color. Apart moderate congestion of the lungs with minimal alveolar edema, no relevant microscopic finding was noted.

There was no other death in any group during the premating, pregnancy or the lactation periods.

From the above clinical history, necropsy and microscopic findings, the above mentioned sporadic deaths were considered to be accidental and without relationship to the treatment with the test item.

Viability index:
P:
Dose-level (mg/kg/day) 0 10 70 500
Viability index (%) 98.1 97.3 98.0 96.6
CIT Historical Control Data for viability index on day 4 pp: minimum = 95.9, maximum = 100%

CLINICAL SIGNS (OFFSPRING)
Description, severity, time of onset and duration of clinical signs: F1: no other effects.

BODY WEIGHT + FOOD CONSUMPTION (OFFSPRING)
BW F1: at 500 mg/kg/day for the males, significantly lower body weight gain (days 1 to 15, -8%, p<0.05)
Food intake F1: at 500 mg/kg/day for the males, significantly lower food consumption (days 1 to 15, -11%, p<0.01) during the first weeks of the premating.

SEXUAL MATURATION (OFFSPRING)
- Offspring toxicity F1 and F2:
F1:
Litter data
Dose-level (mg/kg/day) 0 10 70 500
Pups delivered (mean number/F) 13.6 14.0 14.4 14.7
Sex-ratio (% of males) 51.8 53.7 50.8 53.0
Pup weight at birth (day 1 pp)(g) 6.7 6.6 6.5 6.5
. Day 1 pp 6.7 6.6(-1%) 6.5(-3%) 6.5(-3%)
. Day 4 pp (pre-culling) 9.6 9.5(-1%) 9.1(-5%) 9.1(-5%)
. Day 7 pp 16.3 15.9(-2%) 15.6(-4%) 15.1(-7%)
. Days 14 pp 34.5 34.7(+1%) 34.0(-1%) 33.5(-3%)
. Day 21 pp 53.8 54.9(+2%) 53.0(-1%) 52.0(-3%)
Body weight change (g)
. Days 1-4 pp 2.9 2.9(0%) 2.7(-7%) 2.6(-10%)
. Days 4-21 pp 44.1 45.4(+3%) 43.7(-1%) 42.9(-3%)
(): difference from controls
CIT Historical Control Data for body weight on day 4 pp: mean = 9.7, mini = 9.5, maxi = 10.0
CIT Historical Control Data for body weight on day 7 pp: mean = 14.5, mini = 13.9, maxi = 16.3
CIT Historical Control Data for body weight on day 21pp: mean = 43.3, mini = 40.6, maxi = 52.0

The litter size at birth showed normal fluctuations among treated and control groups, being slightly higher in the treated groups, compared to the control group; this finding was considered to be of fortuitous occurrence. The sex ratio was similar in all groups. Very few deaths within control range, not related to treatment. No macroscopic post-mortem changes. Anouria (absence of tail) was observed in one pup from dam given 10 mg/kg/day or 500 mg/kg/day. Since this finding was low in incidence and not dose-related, it was considered to have occurred by chance.
The other observations (necrosis on hindlimb, cold to the touch and scattered hair) were low in incidence and randomly distributed within the groups, thus, they were considered not to be related to the treatment. There were no effects on reflex development. No effects on auditory function, visual function and no significant effect on spontaneous locomoter activity.

F2:
Litter data
Dose-level (mg/kg/day) 0 10 70 500
Litter size at birth(mean/F) 13.6 13.4 14.9 14.3
Sex-ratio (% of males) 52.7 49.2 50.2 52.2
Pup weight at birth (day 1 pp) (g) 6.6 6.7 6.4 6.7
Body weight (g)
. Day 1 pp 6.6 6.7(+1%) 6.4(-3%) 6.7(+1%)
. Day 4 pp (pre-culling) 9.1 9.3(+2%) 9.3(+2%) 9.0(-1%)
. Day 7 pp 15.4 15.4(0%) 15.4(0%) 14.6(-5%)
. Day 14 pp 33.0 33.2(0%) 33.1(0%) 31.2(-5%)
. Day 21 pp 52.0 51.9(0%) 51.7(-1%) 48.8(-6%)
Body weight change (g)
. Days 1-4 pp 2.5 2.6(+4%) 2.8(+12%) 2.3(-8%)
. Days 4-7 pp 6.1 6.1(0%) 6.3(+3%) 5.6(-8%)
. Days 4-21 pp 42.6 42.6(0%) 42.6(0%) 39.9(-6%)
(): difference from controls
CIT Historical Control Data for body weight on day 4 pp: mean=9.7, mini=9.5, maxi=10.0
CIT Historical Control Data for body weight on day 7 pp: mean=14.5, mini=13.9, maxi=16.3
CIT Historical Control Data for body weight on day 21pp: mean= 43.3, mini=40.6, maxi= 52.0

No effect was recorded on pup survival over the lactation period. The slightly lower viability index recorded in the control group was the consequence of one entirely decedent litter. There were no notable clinical signs among the pups.
The pups body weight and body weight gain at 10 and 70 mg/kg/day were not affected by the treatment during the whole lactation period. At 500 mg/kg/day, the body weight was similar to the control group value while slightly non-significant lower body weight and body weight gain were recorded after one week of birth until the end of the lactation period. These differences were clearly not related to the treatment period since the control value on day 21 post-partum was particularly higher and within the highest body weight values recorded in CIT historical control data. No effects on the sex ratio, reflex development or sperm parameters.

ORGAN WEIGHTS (OFFSPRING)
Organ weight changes P, F1 and F2:
An increased spleen weight was observed in 500 mg/kg day P and F1 males. It was considered that the differences in spleen weight were most probably secondary to the anaemia noted among the animals and consequently of no toxicological importance. Other differences in organ weights in P, F1 and F2 were not dose-related and/or without the same trend in both sexes. As the differences in thyroid and thymus weight were minimal and not dose-related, they were considered to be of no toxicological importance.

GROSS PATHOLOGY (OFFSPRING)
Gross pathology incidence and severity:
The only macroscopic findings observed were those which have been found to occur spontaneously in the untreated laboratory rat of this strain and age. They were therefore considered to be of no toxicological importance.

HISTOPATHOLOGY (OFFSPRING)
Histopathology incidence and severity, P, F1 and F2:
See above (parental animals).

OTHER FINDINGS (OFFSPRING)

Overall reproductive toxicity

Reproductive effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
No effect was observed on mating, fertility, gestation, fecundity or delivery at any dose-level for either generation.
No effect was recorded on litter parameters and on pre and post-natal development of either generation at any dose-level.
Therefore, the No Observed Effect Level (NOEL) for parental toxicity is 10 mg/kg/day for the male and 70 mg/kg/day for the female.
The No Observed Effect Level (NOEL) for mating behaviour, fertility and gestation, of each generation and for development, growth and survival of each progeny is 500 mg/kg/day.
Executive summary:

The study was designed to investigate the effects of the test material, sodium chlorate, on the growth and reproductive performance of the Sprague-Dawley rat and complies with OECD Guideline 416. A former one-generation dose-range finding study was performed to select dose-levels for this two-generation study. The study followed the principles of GLP. The test material was administered orally, by gavage. In the P generation three groups of 25 male and 25 female rats received the test material 10 weeks before mating and during mating, pregnancy and lactation. In the F1 generation three groups of 25 male and 25 female rats received the test material at weaning, on day 22 post-partum, until weaning of the F2 generation. The dose levels were 10, 70 and 500 mg/kg/day. The control group (25 makes and 25 females in both generations) received vehicle (purified water) alone.

For parent of the F0 generation, sign of toxicity was substantiated by a decrease in red blood cells and hemoglobin concentration levels at 500 mg/kg/day. For parent of the F1 generation, significantly lower body weight gain and food consumption were observed during the first week of treatment at 500 mg/kg/day. For both parent males and females of both generations given 500 mg/kg/day, signs of slight to moderate follicular hyperplasia and signs of slight to moderate hyperactivity of the thyroid glands were recorded. Signs of hyperactivity were also observed for males of both F0 and F1 generation at 70 mg/kg/day.

No effect was observed on mating, fertility, gestation, fecundity or delivery at any dose-level for either generation.

No effect was recorded on litter parameters and on pre and post-natal development of either generation at any dose-level.

Therefore, the No Observed Effect Level (NOEL) for parental toxicity is 10 mg/kg/day for the male and 70 mg/kg/day for the female. Due to an increase in spleen follicular cell hyperplasia and grade 4 follicular hyperactivity of the thyroids in males and females at 500 mg/kg bw/day in F0 and F1 parents, which is a non-adverse effects, the parental NOAEL was 70 mg/kg/day in males and females.

The No Observed Effect Level (NOEL) for mating behaviour, fertility and gestation, of each generation and for development, growth and survival of each progeny is 500 mg/kg/day.