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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
screening for reproductive / developmental toxicity
Remarks:
based on test type (migrated information)
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
GLP-Guideline Study, tested with the source substance CAS 112-85-6. In accordance to ECHA guidance document "Practical guide 6: How to report read-across and categories (May 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
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)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Docosanoic acid
- Physical state: white powder
- Analytical purity: 85.9 %
- Lot/batch No.: 60805X
- Impurities (identity and concentrations): C14-C20 fatty acids: 10.9 %, C24 fatty acids: 2.3 %
- Storage condition of test material: at room temperature in the dark

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Japan, Hino, Tokyo
- Age at study initiation: 8 weeks
- Weight at study initiation: male: 312.1 - 363.7 g; female: 205.3 - 230.8 g
- Housing: metal wire floor cages
- Diet (ad libitum): CE-2, CLEA Japan
- Water (ad libitum): tap water
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 ± 1
- Humidity (%): 50 - 65
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
olive oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
prepared more frequently than once a week; aliquots were kept by each concentration refrigerated in airtight conditions

VEHICLE
- Justification for use and choice of vehicle (if other than water): due to insolubility in water
- Amount of vehicle (if gavage): 5 mL/kg bw
- Lot/batch no. (if required): V6H2050
Details on mating procedure:
- M/F ratio per cage: 1/1
- Length of cohabitation: up to two weeks
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- Further mating after two unsuccessful attempts: no
- After successful mating each pregnant female was caged (how): individually
Analytical verification of doses or concentrations:
yes
Duration of treatment / exposure:
- males: 42 days
- females: from 14 days prior to mating to day 3 of lactation
Frequency of treatment:
daily
Details on study schedule:
- Age at mating of the mated animals in the study: 10 weeks
Doses / concentrations
Remarks:
Doses / Concentrations:
100, 300, 1000 mg/kg bw/d
Basis:
nominal conc.
No. of animals per sex per dose:
13 in each group
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: based on preliminary result in a 14 day-repeated dose toxicity study, where no signs of toxicity were found

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once a day
- Cage side observations checked in table were not included.

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: males: days 1, 8, 15, 22, 29, 36, 42; pregnancy females: premating days 1, 8, 15; pregnancy days: 0, 7, 14, 20; lactation days: 0, 4; non pregnancy females: day 1, 8, 15, 22, 25

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- 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: No

HAEMATOLOGY: Yes (males only)
- Time schedule for collection of blood: prior to autopsy
- Anaesthetic used for blood collection: Yes (identity): pentobarbital sodium
- Animals fasted: 18 - 24 hours before sacrifice
- How many animals: all surviving animals
- Parameters checked: red blood cell count (RBC), white blood cell count (WBC), haemoglobin content (Hb), mean corpuscular volume (MCV), ahematocrit (Ht), mean corpuscular haemoglobin content (MCH), mean corpuscular haemoglobin concentration (MCHC)

CLINICAL CHEMISTRY: Yes (males only)
- Animals fasted: 18 - 24 hours before sacrifice
- How many animals: all surviving animals
- Parameters checked: total protein, albumin, total cholesterol concentration, glucose, urea nitrogen, creatinine, alkaline phosphatase activity, GOT, GPT, γ-GTP, triglyceride concentration, inorganic phosphorus, total bilirubin, calcium, sodium, potassium, chlorine, A/G ratio

URINALYSIS: No
Sperm parameters (parental animals):
Parameters examined in all male parental generations:
testis weight, epididymis weight
Litter observations:
STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: no

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: all surviving animals
- Maternal animals: all surviving animals

HISTOPATHOLOGY / ORGAN WEIGHTS
Organ weights:
male: heart, liver, kidneys, thymus, testes, epididymides
female: heart, liver, kidneys, thymus

Pathological findings and Histopathology (control and 1000 mg/kg bw group):
male: heart, liver, spleen, kidney, adrenal, testis, epididymis, brain, thymus, bladder
female: brain, liver, spleen, thymus, kidney, adrenal, bladder, heart, ovary, uterus
Postmortem examinations (offspring):
SACRIFICE
- The F1 offspring not selected as parental animals were sacrificed at 4 days of age.
- These animals were subjected to postmortem examinations (macroscopic examination) as follows: external malformations, visceral malformations
Statistics:
Yates test, Mann-Whitney U test, Fisher exact test, Bartlett test, Dunnett test, Scheffe test, Kruskal-Wallis test
Reproductive indices:
- Copulation index = (number of copulated pairs / number of pairs mated) x 100
- Fertility index = (number of pregnant animals / number of copulated pairs) x 100
- Gestation index = (number of pregnant females with pups alive / number of pregnant females) x 100
- Implantation index = (number of implantation sites / number of corpora lutea) x 100
Offspring viability indices:
- Delivery index = (number of pups born / number of implantation sites) x 100
- Birth index = (number of pups alive on day 0 / number of implantation sites) x 100
- Live birth index = (number of pups alive on day 0 / number of pups born) x 100
- Sex ratio on day 0 = (number of males pups alive on day 0 / number of female pups alive on day 0) x 100
- Viability index = (number of pups alive on day 4 / number of pups alive on day 0) x 100

Results and discussion

Results: P0 (first parental animals)

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
- Males: no deaths or abnormalities in general condition were observed in any of the treated groups
- Females: no deaths were observed in any treated group

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Males: significant increase (p<0.01) compared to control was observed in 100 mg/kg group between 8 - 15 days and between 15 - 29 days. However, since no change was observed in other groups, the effect was not considered to be related to the dosing of compound. No changes in food consumption related to the dosing of compound were observed
- Females: no significant changes in body weight were noted and there were no changes related to the dosing of compound in body weight gain and food consumption. A significant decrease (p<0.01) compared to control was observed during lactation in 100 mg/kg dosing group. However, since no other changes in food consumption were noted in 300 mg/kg and 1000 mg/kg dosing groups, the effect was not considered to be related to the dosing of compound.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There were no significant differences in number of corpora lutea, implantation rate, number of implantations and all other reproductive parameters in all treated groups compared to the control group.

ORGAN WEIGHTS (PARENTAL ANIMALS)
Males: in 100 mg/kg bw males, the actual weight ratio of liver weight (p <0.05) compared to control values were increased. No other significant differences were found in all groups. Thus, this finding lacks a dose-dependency and was regarded as incidental.
- Females: kidney weight was significantly reduced (p<0.05) in the 300 mg/kg bw group. No other weight changes were noted. Thus, this finding lacks a dose-dependency and was regarded as incidental.

GROSS PATHOLOGY (PARENTAL ANIMALS)
Males:
- Heart: myocardial degeneration was noted in one animal of the control group and the 1000 mg/kg bw group, respectively
- Liver: periportal fatty change of the liver was found in all animals of the control and the high dose group. Focal necrosis was noted in one animal of the high-dose group.
- Spleen: all animals of the control and the high-dose group showed brown pigment deposits of the spleen as well as extramedullary haematopeiosis
- Kidney: while fibrosis was only found in 1/13 animals of the control group, eosinophilic bodies and basophilic tubuli in the cortex were noted in animals of both control and high dose groups, respectively
- Adrenal gland: one animal of the high-dose group showed fibrosis
- Testis: atrophy of the seminiferous tubules was observed in two animals of the 1000 mg/kg dose group, with one animal affected on both sides and one side affected in the other animal. No other abnormalities were noted.
- Epididymis: abnormal sperm granuloma was found in one animal of the control group
- Brain: no abnormal findings noted
- Thymus: no abnormal findings noted
- Bladder: no abnormal findings noted

Females:
- Brain: one animal of the high-dose group showed abnormal mineral deposition in the thalamus
- Liver: focal necrosis and fibrosis was found in one animal of the control group, while one animal of the high-dose group showed only focal necrosis
- Spleen: brown pigmentation and extramedullary haematopeiosis was found in animals of the control and the high-dose group, but no varying degrees of frequency was observed
- Thymus: atrophy and bleeding was observed in animals of both groups, control and high-dose group, respectively
- Kidney: basophilic tubuli of the cotex and a dilatation of the renal pelvis was seen in the control and high-dose group
- Adrenal gland: cortical necrosis was observed in one animal of the control group
- Heart: no abnormal findings noted
- Bladder: no abnormal findings noted

Effect levels (P0)

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no adverse substance -related findings on fertility were noted

Results: F1 generation

Details on results (F1)

VIABILITY (OFFSPRING)
No change in number of birth, birth rate, infant live birth rate, infant survival and birth rates at day 4 was found in all dose groups compared to the values of the control group.

BODY WEIGHT (OFFSPRING)
No difference in bodyweight of pups of the dose groups and the control group was found.

GROSS PATHOLOGY (OFFSPRING)
No morphological abnormalities were found in all groups.

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Table 1. Summary of development up of pups from dams treated orally with docosanoic acid in the combined repeat dose and reproductive/developmental toxicity screening test: Mean± S.D (N)

Dose group (mg/kg)

0

100

300

1000

Number of pregnant females

13

12

12

13

Number of pregnant females with live pups

13

12

12

13

Gestation index

100

100

100

100

Gestation length in days

22.2±0.4 (13)

22.4±0.5 (12)

22.3±0.5 (12)

22.2±0.4 (13)

Number of corpora lutea

16.6±1.6 (13)

16.7±1.8 (12)

16.8±2.3 (12)

16.2±1.5 (13)

Number of implantation sites

16.1±1.5 (13)

15.8±2.1 (12)

16.0±1.5 (12)

15.2±3.1 (13)

Implantation index

96.9±5.1 (13)

94.8±7.1 (12)

96.1±6.0 (12)

93.1±15.2 (13)

Day 0 of lactation

 

 

 

 

Number of pups born

15.2±1.6 (13)

14.8±2.2 (12)

15.2±1.5 (12)

14.3±2.7 (13)

Delivery index

94.5±8.0 (13)

93.5±3.9 (12)

94.9±4.3 (12)

94.9±6.2 (13)

Number of live pups

14.9±1.6 (13)

14.3±2.2 (12)

15.1±1.6 (12)

14.1±2.7 (13)

Birth index

93.1±8.8 (13)

90.7±8.7 (12)

94.3±5.1 (12)

93.5±7.2 (13)

Live birth index

98.5±2.8 (13)

97.0±8.5 (12)

99.4±2.2 (12)

98.5±4.0 (13)

Sex ration on day 0

50.0±11.3 (13)

46.7±9.8 (12)

54.8±12.3 (12)

48.9±13.4(13)

Day 4 of lactation

 

 

 

 

Number of live pups

14.7±1.4 (13)

13.0±4.7 (12)

15.1±1.6 (12)

14.1±2.7 (13)

Viability index

98.6±2.7 (13)

89.4±28.8 (12)

100.0±0.0 (12)

100.0±0.0 (13)

Sex ration on day 4

49.8±11.5 (13)

46.3±10.3 (11)

54.8±12.3 (12)

48.9±13.4(13)

Applicant's summary and conclusion