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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Justification for type of information:
Data is from Ministry of Health, Labor and Welfare (MHW) report

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
Principles of method if other than guideline:
One generation reproductive toxicity test of test chemical was carried out and the toxicity of reproductive to male and female animals of test chemical was examined
GLP compliance:
yes
Limit test:
no
Justification for study design:
No data available

Test material

Constituent 1
Chemical structure
Reference substance name:
2-Naphthol
Cas Number:
135-19-3
Molecular formula:
C10H8O
IUPAC Name:
2-Naphthol
Test material form:
solid: flakes
Details on test material:
- Name of test material (as cited in study report):2-naphthol
- Molecular formula (if other than submission substance): C10H8O

- Molecular weight (if other than submission substance):144.172

- Substance type: Organic
- Physical state: Solid: grey flakes
- Impurities (identity and concentrations): purity: 99.6%, gray white flake containing 0.3% of test chemical as an impurity

Test animals

Species:
rat
Strain:
other: Sprague-Dawley strain (Crj: CD) rats
Details on species / strain selection:
No data available
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Tsukuba breeding center, Charles River Japan Co., Ltd.
- Age at study initiation: No data available
- Weight at study initiation: No data available
- Fasting period before study: No data available
- Housing: housed in a metallic wire mesh floor cage in a breeding room
- Use of restrainers for preventing ingestion (if dermal): yes/no: No data available
- Diet (e.g. ad libitum): No data available
- Water (e.g. ad libitum): tap water, provided ad libitum
- Acclimation period: No data available

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 ± 1 ° C
- Humidity (%): 50 to 65%
- Air changes (per hr): about 15 times / hour
- Photoperiod (hrs dark / hrs light): lighting for 12 hours

Administration / exposure

Route of administration:
oral: gavage
Type of inhalation exposure (if applicable):
not specified
Remarks on MMAD:
No data available
Vehicle:
CMC (carboxymethyl cellulose)
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: The dosing solution was prepared by mixing the test chemical in vehicle with a magnetic stirrer

DIET PREPARATION
- Rate of preparation of diet (frequency): No data available
- Mixing appropriate amounts with (Type of food): No data available
- Storage temperature of food: No data available

VEHICLE
- Justification for use and choice of vehicle (if other than water):No data available
- Concentration in vehicle: No data available
- Amount of vehicle (if gavage): 5ml/kg
- Lot/batch no. (if required): No data available
- Purity:No data available
Details on mating procedure:
Matings were conducted in males and females 1: 1 within the same group for a period of 3 weeks, and confirming the presence of sperm in the vaginal smear and confirming the vaginal plug every morning.
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
No data available
Duration of treatment / exposure:
10 weeks (71 days of administration)
Frequency of treatment:
Daily
Details on study schedule:
No data available
Doses / concentrations
Remarks:
0 (vehicle control)= 25male and 25female
10mg/kg=25male and 25female
40mg/kg=25male and 25female
160 mg/kg=25male and 25female
No. of animals per sex per dose:
0 (vehicle control)= 25male and 25female
10mg/kg=25male and 25female
40mg/kg=25male and 25female
160 mg/kg=25male and 25female
Control animals:
yes, concurrent vehicle
Details on study design:
Animals were orally administered from 10 weeks of age including mated up to 3 weeks. The males were necropsied after one week passed after the mating period. Females were allowed to spontaneously deliver after mating and necropsied with their babies on nursing 21th. Both males and females continued to be administered until the day before necropsy, during which the general condition of the parent animal, weight gain and changes in food intake were observed, and at the same time the reproductive ability, including delivery and lactation of the parent animal, and weaning of the infant was observed.
Positive control:
No data available

Examinations

Parental animals: Observations and examinations:
Parent animals were observed for mortality, general condition, change in weight, food intake, estrus cycle assessment.
Oestrous cyclicity (parental animals):
Estrus cycle were determined before 2 weeks of start of mating confirmation day, two weeks before the start of administration and two weeks after the start of the administration.
Sperm parameters (parental animals):
Spermatogenesis cycle was observed in males
Litter observations:
Number of births, litter count and Weight measurement
Postmortem examinations (parental animals):
Animals were sacrificed to determined presence or absence of abnormalities of major organs thoracic abdomen, including the pituitary glands, stomach, testis, epididymis, coagulated glands, seminal vesicles, and prostate in males and pituitary, stomach, ovary, uterus, cervix and vagina in females
Postmortem examinations (offspring):
Offspings were sacrificed to determined presence or absence of abnormality on the external surface
Statistics:
Fisher's direct probability test 1) was carried out on frequency of type of sex cycle, mating rate, conception rate, morphological abnormality frequency of babiesAccording to histopathological examination findings, the Mann-Whitney U test 2)) shows the grade-separated data, and the total value of the positive grade is obtained by Fisher's direct probability one-sided test 3) between the control group and each test substance administration group Significant difference test was carried out. For the other data, we tested the uniformity of variance of each group by Bartlett method 4) , with the value obtained for each individual, or the average value for each litter as one sample . If the variance is uniform, a one-way analysis of variance 4) was performed, and when significance was observed between the groups, multiple comparisons were performed according to the Dunnett method 5) . On the other hand, Kruskal-Wallis 6) rank test is performed when the variance is 0 in any group and when the variance is not uniform, and if significance is observed between the groups.
Reproductive indices:
Conception rate was determined
Offspring viability indices:
No data available

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
no effects observed
Description (incidence and severity):
Nasal discharge, eyelid ptosis or closed eyes, in group administered with 40 mg / kg or more but not in 160mg/kg group , lacrimation in 160 mg / kg administration group was transiently observed Salivation was observed in each administration group of the test substance.
Dermal irritation (if dermal study):
not specified
Mortality:
no mortality observed
Description (incidence):
In males, one patient in the 160 mg / kg dose group died on the 60th day of administration.
In females, there were no deaths or moribund
Body weight and weight changes:
no effects observed
Description (incidence and severity):
No significant difference between the control group and each test group administered group
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
In males no change in food consumption were observed, however in females no change in food consumption uring the period before mating, but significantly lower values than control group, after pregnancy and during the nursing stage
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
Spontaneous locomotor reduction and salivation were observed transiently after administration and no abnormality was observed in both treated males and femlaes. There was a decrease in locomotor activity, eyelid ptosis or closed eyes, and nasal discharge in group administered with 40 mg / kg or more, lacrimation in 160 mg / kg administration group.
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Histopathological findings: non-neoplastic:
effects observed, non-treatment-related
Description (incidence and severity):
No abnormality was observed in pituitary gland. In males, in each case in the 40 mg / kg and 160 mg / kg administration groups, the spermatogonia of the spermatogenic cells in the 14 th stage of the spermatogenesis cycle mild degeneration was observed, and cell debris was observed in the lumen of the epididymis in the example of 40 mg / kg administration group. Unilateral seminal vesicle atrophy was observed in each group including the control group. no avnormality were seenon seminal vesicle and Coagulated glands In females, no abnormality was observed in the pituitary gland, stomach, ovary, uterus, cervix and vagina.

Histopathological findings: neoplastic:
not specified
Other effects:
effects observed, treatment-related
Description (incidence and severity):
Hair loss was observed in all the treated animals

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
No significant difference were observed in estrus cycle after administration in each group including the control group
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
Description (incidence and severity):
No significant difference between the conception rate, number of estrus periods in control and treated groups at 10, 40 and 160mg/kg. There was no significant difference in number of implantation between the control group and each test chemical treated groups.

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
160 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
gross pathology
histopathology: non-neoplastic
reproductive function (oestrous cycle)
reproductive function (sperm measures)
reproductive performance

Target system / organ toxicity (P0)

Critical effects observed:
not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not specified
Mortality / viability:
mortality observed, treatment-related
Description (incidence and severity):
Deaths observed in 4 offspings of control group and 2 offsping of 10 mg / kg administration group, respectively. In addition, 3 out of 6 cases in the 40 mg / kg administration group and 22 cases out of 27 cases in the 160 mg / kg administration group were judged as stillbirth
Body weight and weight changes:
no effects observed
Description (incidence and severity):
There was no significant difference between male and female between the control group and each test group administered group at any time.
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:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Histopathological findings:
no effects observed
Description (incidence and severity):
At necropsy of born pups, morphological changes including malformations and mutations were observed in born pups 1-2 in each group including the control group.
Other effects:
not specified

Developmental neurotoxicity (F1)

Behaviour (functional findings):
not specified

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not specified

Effect levels (F1)

Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
40 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
body weight and weight gain
histopathology: non-neoplastic

Target system / organ toxicity (F1)

Critical effects observed:
not specified

Overall reproductive toxicity

Key result
Reproductive effects observed:
not specified
Treatment related:
not specified

Applicant's summary and conclusion

Conclusions:
From the observation and results, the NOAEL for P0 generation and F1 generation was considered to be 160mg/kg/day and 40mg/kg/day respectively.
Executive summary:

In the present study, one generation reproductive toxicity test of test chemical was carried out and the toxicity of reproductive to male and female animals of test chemical was examined. In the study, animals were orally administered from 10 weeks of age including mated up to 3 weeks. The males were necropsied after one week passed after the mating period. Females were allowed to spontaneously deliver after mating and necropsied with their babies on nursing 21th. Both males and females continued to be administered until the day before necropsy, during which the general condition of the parent animal, weight gain and changes in food intake were observed, and at the same time the reproductive ability, including delivery and lactation of the parent animal, and weaning of the infant was observed. The results of the parenteral examination revealed that, no mortality in treated animals at 10, 40 and 160mg/kg/day for 10 weeks,including mating period, the clinical signs examination of animlas shows, nasal discharge, eyelid ptosis or closed eyes, in group administered with 40 mg / kg or more but not in 160mg/kg group , lacrimation in 160 mg / kg administration group was transiently observed. Salivation was observed in each administration group of the test substance.No test chemical related chnages on food consumption and body weight changes were observed. Spontaneous locomotor reduction and salivation were observed transiently after administration and no abnormality was observed in both treated males and femlaes.  There was a decrease in locomotor activity, eyelid ptosis or closed eyes, and nasal discharge in group administered with 40 mg / kg or more, lacrimation in 160 mg / kg administration group. There was no change depending on the dose of the test substance in reproductive organsof male and females. The histopathological study relealed no abnormality in pituitary gland. In males, in each case in the 40 mg / kg and 160 mg / kg administration groups, the spermatogonia of the spermatogenic cells in the 14 th stage of the spermatogenesis cycle mild degeneration was observed, and cell debris was observed in the lumen of the epididymis in the example of 40 mg / kg administration group.  Unilateral seminal vesicle atrophy was observed in each group including the control group. No abnormality were seen on seminal vesicle and Coagulated glands In females, no abnormality was observed in the pituitary gland, stomach, ovary, uterus, cervix and vagina. The fetal examination results revealed, deaths in 4 offspings of control group and 2 offsping of 10 mg / kg administration group, respectively. In addition, 3 out of 6 cases in the 40 mg / kg administration group and 22 cases out of 27 cases in the 160 mg / kg administration group were judged as stillbirth, but no clinical signs of toxicity on survived pups. There was no significant difference in body weight in male and female  between the control group and each test group administered group at any time. No gross pathological changes were observed, At necropsy of born pups, morphological changes including malformations and mutations were observed in  born pups 1-2 in each group including the control group. From the observation and results, the NOAEL for P0 generation and F1 generation was considered to be 160mg/kg/day and 40mg/kg/day respectively.