2'-acetonaphthone

Toxicity to reproduction

Administrative data

Endpoint:

one-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

Data from secondary source

Data source

Reference

Reference Type:

other: secondary source

Title:

One generation reproduction developmental toxicity study in Wistar rats

Author:

European Food Safety Agency (EFSA)

Year:

2010

Bibliographic source:

Additional Report to the DAR for test material ,2010

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 study of test material was performed on male and female Wistar rats.

GLP compliance:

not specified

Limit test:

no

Justification for study design:

No data available

Test material

Test material information

Constituent 1

Reference substance name:

2-naphthyloxyacetic acid

EC Number:

204-380-0

EC Name:

2-naphthyloxyacetic acid

Cas Number:

120-23-0

Molecular formula:

C12H10O3

IUPAC Name:

2-naphthyloxyacetic acid

Details on test material:

- Name of test material: 2-naphthyloxyacetic acid
- Molecular formula: C12H10O3
- Molecular weight: 202.208 g/mol
- Substance type: Organic

Test animals

Species:

rat

Strain:

Wistar

Details on species / strain selection:

No data available

Sex:

male/female

Details on test animals or test system and environmental conditions:

No data available

Administration / exposure

Route of administration:

oral: feed

Type of inhalation exposure (if applicable):

not specified

Remarks on MMAD:

No data available

Vehicle:

not specified

Details on exposure:

No data available

Details on mating procedure:

No data available.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data available

Duration of treatment / exposure:

Males were treated for 10 weeks before mating and during the mated period and females for at least two weeks before mating, during 3 weeks of mating and pregnancy till the 21st day of lactation. The dams were allowed naturally deliver after mating and necropsied with their offspring on the 21st day of lactation.

Frequency of treatment:

daily

Details on study schedule:

No data available

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

500 mg/kg bw/day

Doses / concentrations 4

Dose / conc.:

2 500 mg/kg bw/day

No. of animals per sex per dose:

Total:200
0 ppm:25 male and 25 female
100ppm:25 male and 25 female
500ppm:25 male and 25 female
2500 ppm:25 male and 25 female

Control animals:

yes

Details on study design:

No data available

Positive control:

No data available

Examinations

Parental animals: Observations and examinations:

Parental animals observation and examinations
CAGE SIDE OBSERVATIONS: yes

DETAILED CLINICAL OBSERVATIONS: Yes
Time schedule: daily

BODY WEIGHT: Yes
Time schedule for examinations: Body weights were recorded weekly during gestation period and at days 1, 4, 7, 14 and 21 during lactation period.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes Food consumption was measured weekly during experimental period. Food intake was recorded on presumed gestation days 7, 14 and 20 and on lactation days 4, 7, 14, 18 and 21.
Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
Time schedule for examinations

Oestrous cyclicity (parental animals):

No data available

Sperm parameters (parental animals):

Yes, sperm morphology, caunt and motility were recorded.

Litter observations:

At birth, the number of pups born, sex and body weight of individual pups on days 1 and 4 were recorded. After standardization of litter size to 8 pups, pups were weighed individually on days 7, 14 and 21 of lactation. On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination. Fertility index for dams, sires and pup survival index were calculated.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving males were sacrificed shortly after the 3 weeks of mating period.
- Maternal animals: The dams were sacriced with their offspring on the 21st day of lactation.
GROSS NECROPSY: Yes. The following tissues and organs were preserved in 10% neutral buffered formalin and submitted to microscopic examination: grossly abnormal tissues, ovaries, uterus, vagina, testes, epididymides, seminal vesicles, prostate, coagulating glands, pituitary gland and target organs of all parental animals. The number of corpora lutea and implantation sites were recorded for all the dams.
HISTOPATHOLOGY / ORGAN WEIGHTS: Yes
Histopathological examination of the parents was initially restricted to preserved organs from control and high dose group animals.

Postmortem examinations (offspring):

SACRIFICE
On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination.

Statistics:

All quantitative variables like body weight and feed intake data were analysed by one-way ANOVA. Comparison of means between treatment groups and vehicle control group were done using Dunnett’s test if the overall treatment ‘F’ test was found to be significant. Pre-implantation loss, post implantation loss, number of corpora lutea, implantations, pre-coital interval and litters size (number) were analysed by one-way ANOVA after suitable transformation. Dunnett’s pair-wise comparison of the treated means with the control mean was done if the group differences were found significant. Z test was performed for testing the differences in proportions for mating and fertility indices and survival indices.

Reproductive indices:

Yes, Fertility index for male and female animals were calculated.

Offspring viability indices:

yes

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality:

not specified

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

There were significant lower body weights from control at high dose in males from weeks 2 to 6 and at week 8 associated with a significant lower food intake at weeks 2 and 8 at high dose in males. There was also a significant decrease in bodyweights at day 20 of the gestation period in females of the high dose group, also observed at days 4, 7 and 14 of lactation period

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

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

There were no test item related microscopic changes in males and females. All single or few incidences of microscopic findings observed in males and females were considered as incidental findings.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

There were no test item related changes in sperm motility, cauda epididymal sperm counts and sperm morphology parameters. However, a statistically significant increase in percentage of abnormal sperms was observed in high dose males but this observed change was within the historical control data. Moreover, no fertility parameters were affected and there were no changes in the testes or epididymis grossly or histopathologically therefore, considered incidental and not related to the treatment.

Reproductive performance:

no effects observed

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

153.8 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

2500ppm

Sex:

male

Basis for effect level:

body weight and weight gain

food consumption and compound intake

organ weights and organ / body weight ratios

gross pathology

reproductive function (sperm measures)

reproductive performance

Remarks on result:

other: No effects on reproductive performance were observed.

2

Dose descriptor:

NOAEL

Effect level:

393.6 mg/kg bw/day (nominal)

Based on:

test mat.

Remarks:

2500 ppm

Sex:

female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

organ weights and organ / body weight ratios

gross pathology

reproductive performance

Remarks on result:

other: no effects on reproductive performance

3

Dose descriptor:

LOAEL

Effect level:

2 500 ppm (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Remarks on result:

other:

Remarks:

Significantly reduced bodyweight in the presence of reduced food consumption

Target system / organ toxicity (P0)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Dermal irritation (if dermal study):

not specified

Mortality / viability:

no mortality observed

Description (incidence and severity):

The mean number of male, female and total pups per litter at all the doses tested were unaffected by treatment

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The weight of male, female pups per litter at all the doses tested were unaffected by treatment

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:

not specified

Other effects:

no effects observed

Description (incidence and severity):

No treatment-related changes were observed in the data of pups up to lactation day 21 at all the doses tested.

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not specified

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not specified

Effect levels (F1)

1

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

153.8 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

viability

mortality

body weight and weight gain

gross pathology

Remarks on result:

other: No developmental toxic effects were observed

2

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

393.6 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

viability

mortality

body weight and weight gain

gross pathology

Remarks on result:

other: No developmental toxic effects were observed

Target system / organ toxicity (F1)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Treatment related:

not specified

Applicant's summary and conclusion

Conclusions:

The No Observed Adverse Effect Level (NOAEL) for maternal and developmental toxicity was considered as 2500 ppm which is equivalent to 153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females, when male and female Wistar rats were treated with 2-naphthyloxyacetic acid orally over one generation. The LOAEL for systemic toxicity was set as 2500 ppm (153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females) based on the significant reduction in body weight and food consumption in the high-dose group in both sexes.

Executive summary:

A one generation reproductive toxicity study of the test chemical was performed according to OECD Guideline 415in male and female Wistar rats. The test material wa smixed in diet at concentrations of0, 100, 500 and 2500 ppm and administered to group of 25 rats/sex/dose group. Males were treated for 10 weeks before mating and during the mated period and females for at least two weeks before mating, during 3 weeks of mating and pregnancy till the 21stday of lactation. The dams were allowed naturally deliver after mating and necropsied with their offspring on the 21stday of lactation.Body weights were recorded weekly during gestation period and at days 1, 4, 7, 14 and 21 during lactation period. Food consumption was measured weekly during experimental period. Food intake was recorded on presumed gestation days 7, 14 and 20 and on lactation days 4, 7, 14, 18 and 21. At birth, the number of pups born, sex and body weight of individual pups on days 1 and 4 were recorded. After standardization of litter size to 8 pups, pups were weighed individually on days 7, 14 and 21 of lactation. On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination. Fertility index formales and femalesand pupsurvival index were calculated. On completion of the gross pathology examination, the following tissues and organs were preserved in 10% neutral buffered formalin and submitted to microscopic examination: grossly abnormal tissues, ovaries, uterus, vagina, testes, epididymides, seminal vesicles, prostate, coagulating glands, pituitary gland and target organs of allparentalanimals. The number of corpora lutea and implantation sites were recorded for all the dams. Histopathological examination of the parents was initially restricted to preserved organs from control and high dose group animals.There were significant lower body weights from control at high dose (2500 ppm) in males from weeks 2 to 6 and at week 8 associated with a significant lower food intake at weeks 2 and 8 at high dose in males. In females a significant decrease in body weights was observed at day 20 of the gestation period at 2500 ppm group, and at days 4, 7 and 14 of lactation period. A statistically significant increase in relative kidney weights at 500 and 2500 ppm in males and at 2500 ppm for males and females was observed. However, the increased kidney weights observed in males and females were minimal in nature (<12%) and were not associated with microscopic changes, hence considered as toxicologically insignificant changes. The relative weight of epididymides increased significantly at 2500 ppm in males but with no related microscopic changes in left epididymides. Further, there were no corresponding change in the weight of right cauda epididymides and epididymal sperm count, therefore the increased epididymal weights were considered as incidental changes. There were no test item related changes in sperm motility, cauda epididymal sperm counts and sperm morphology parameters. In the 2500 ppm group, a statistically significant increase in percentage of abnormal sperms was observed, although this observed change was within the historical control data. Moreover, no fertility parameters were affected and there were no changes in the testes or epididymis grossly orhistologically.No test chemical-related gross and microscopic changes were found in males and females at any dose groups.The mean number and weight of male, female and total pups per litter at all the doses tested were unaffected by treatment. No treatment-related changes were observed in the data of pups up to lactation day 21 at all the doses tested. As no changes of toxicological significance noted among the rats that received dietary administration of the test chemical over one generation up to the dose level of 2500 ppm which, is equivalent to 153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females, this dose level is considered to be NOAEL for systemic and reproductive toxicity in parental animals and toxicity to offspring, under the test conditions and doses employed. The LOAEL for systemic toxicity was set as 2500 ppm (153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females) based on the significant reduction in body weight and food consumption in the high-dose group in both sexes.