Difluoroacetic acid

Toxicity to reproduction

Administrative data

Endpoint:

fertility, other

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

publication

Title:

Sub-chronic Exposure to Dibromoacetic Acid, a Water Disinfection By-product, Does Not Affect Gametogenic Potential in Mice

Author:

N. M. Weber, H. R. Sawyer, M. E. Legare, and D. N. R. Veeramachaneni

Year:

2006

Bibliographic source:

TOXICOLOGICAL SCIENCES 89(1), 325–330 (2006)

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other:

Principles of method if other than guideline:

In a one-generation study , the developmental and reproductive effects of subchronic,
low-dose exposure to dibromoacetic acid (DBA) in C57Bl/6J mice.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Dibromoacetic acid

EC Number:

211-165-5

EC Name:

Dibromoacetic acid

Cas Number:

631-64-1

IUPAC Name:

dibromoacetic acid

Test material form:

other: Liquid

Details on test material:

- Name of test material (as cited in study report): DIBROMOACETIC ACID
- Molecular formula (if other than submission substance): C2H2Br2O2
- Molecular weight (if other than submission substance): 217.86
- Substance type: Organic
- Physical state: Liquid
- Impurities (identity and concentrations): ----

Test animals

Species:

mouse

Strain:

other: C57Bl/6J mice

Sex:

male/female

Details on test animals or test system and environmental conditions:

-Source: Jackson Laboratory
-Age: Six- to eight-week-old
-Housing: Mice were housed in plastic tubs with cedar chip bedding
(Females were housed 4/tub and males were housed individually. )
-Water: ad libitum; deionized water
-Diet: ad libitum; Teklad 8640 mouse chow
- Acclimation period: two weeks


ENVIRONMENTAL CONDITIONS:
Temperature: 18°C to 26°C (64°F to 79°F);
Humidity (%): 30%to 70%.
Photoperiod: 12:12 h light:dark cycle

Administration / exposure

Route of administration:

oral: drinking water

Type of inhalation exposure (if applicable):

not specified

Vehicle:

water

Details on exposure:

Details on exposure
PREPARATION OF DOSING SOLUTIONS:
Dosing solutions were prepared by adding DBA to deionized water and bringing the pH to 6.8–7.4 using 1N NaOH. Stock solutions were made twice weekly.

DIET PREPARATION
- Rate of preparation of diet (frequency): Not Available
- Mixing appropriate amounts with (Type of food): Not Available
- Storage temperature of food: Not Available

VEHICLE
- Justification for use and choice of vehicle (if other than water): Not Available
- Concentration in vehicle: Not Available
- Amount of vehicle (if gavage): Not Available
- Lot/batch no. (if required): Not Available
- Purity: Not Available

Details on mating procedure:

- M/F ratio per cage: 1:1 ratio
- Length of cohabitation: Males were placed with females at 6:00 P.M. and removed at 6:00 A.M. the following morning
- Proof of pregnancy: [vaginal plug / sperm in vaginal smear] referred to as [day 0 / day 1] of pregnancy Presence of a vaginal plug was designated day 0 of gestation
- After … days of unsuccessful pairing replacement of first male by another male with proven fertility. Males and un-mated females were given a day of rest between successive breedings.
- Further matings after two unsuccessful attempts: [no / yes (explain)] Not Available
- After successful mating each pregnant female was caged (how): Pregnant females were separated and housed individually
- Any other deviations from standard protocol: Not Available

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

Not Available

Duration of treatment / exposure:

Study I: 3 weeks (pre-pubertal pups)
Study II: 7 weeks (neo-pubertal pups)

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 5, 50 mg/kg/day
Basis:
nominal in water

No. of animals per sex per dose:

1) F1, pre-puberty
Control:
7-10 males and 7-10 females
5 mg/kg/day: 7-10 males and 7-10 females
50 mg/kg/day: 7-10 males and 7-10 females

2) F1, neo-puberty
Control:
15-17 males and 15-17 females
5 mg/kg/day: 15-17males and 15-17 females
50 mg/kg/day: 15-17males and 15-17 females

Control animals:

yes, concurrent vehicle

Details on study design:

Not Available

Positive control:

Not Available

Examinations

Parental animals: Observations and examinations:

Pre-pubertal (3-week-old) evaluation:
Viscera and reproductive organs were examined for any abnormalities. Weights were taken for liver, kidneys, testes, and ovaries. Right testes and ovaries were fixed in 4% glutaraldehyde for 24 h then stored in 2% cacodylate while left testes and ovaries were fixed in Bouin’s solution for 48 h then stored
in 70% alcohol until further processing for histopathology

Neo-pubertal (7-week-old) evaluation:
Procedures for necropsy and tissue collection were similar to those performed at 3 weeks except that for a group of 10–11 males/treatment, half of the right testis was fixed in Bouin’s solution and the remaining half and the epididymis were fixed in glutaraldehyde. The left testis and epididymis were weighed separately and frozen in liquid nitrogen for determination of daily sperm production and epididymal sperm reserves. Frozen tissues were maintained at -80°C until processing for determination of sperm counts

Oestrous cyclicity (parental animals):

Not Available

Sperm parameters (parental animals):

No significant difference was noted between control and dosed males in sperm, seminiferous epithelial and endocrine parameters. There was no difference between control and dosed mice in testis sperm counts or DSP. DGEL did not differ significantly between control and dosed animals.

Sperm Parameters for Neo-pubertal Male Mice (7 Week) Exposed to 0, 5, or 50 mg DBA/kg/day
Dose group
0 5 50
Total sperm/testis (x106) 11.94 ± 0.25 13.53 ± 1.25 10.78 ± 0.71
Daily sperm production (x106/g testis) 30.43 ± 1.18 34.49 ± 3.68 30.20 ± 1.35
Total sperm /epididymis (x106) 14.07 ± 0.93 14.56 ± 1.44 12.05 ± 1.54

Note. Values represent mean ± SEM.

Histopathological Changes in Seminiferous Epithelium and Degree of Germinal Epithelial Loss (DGEL) for Neo-pubertal Male Mice (7 Week) Exposed to 0, 5, or 50 mg DBA/kg/day

Seminiferous tubules (%)
classified as Dose group
0 5 50
Grade 0 80.2 81.3 78.9
Grade 1 19.8 18.7 20.6
Grade 2 0 0 0.2
Grade 3 0 0 0.3
Grades 4–7 0 0 0
DGEL 4.94 ± 0.35 4.68 ± 0.41 5.59 ± 0.81

Note. Values represent mean ± SEM.

Litter observations:

Not Available

Postmortem examinations (parental animals):

Not Available

Postmortem examinations (offspring):

Not Available

Statistics:

Statview was used for all statistical analyses. All parameters were analyzed using ANOVA with a Tukey/Kramer post-hoc test. Body weight was used as a covariate for weights of liver, kidney, testis, and ovary. Body length was used as a covariate for ano-genital distance. A level of significance of p ≤0.05 was used for all tests.

Reproductive indices:

Not Available

Offspring viability indices:

Not Available

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

not specified

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

not specified

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

not specified

Effect levels (P0)

Remarks on result:

not measured/tested

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

not specified

Body weight and weight changes:

not specified

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Description (incidence and severity):

Testes of high dose pre-pubertal males were significantly larger than control males of the same age, but at 7 weeks of age high dose males had significantly smaller testes than control males

Gross pathological findings:

not specified

Histopathological findings:

not specified

Effect levels (F1)

1

Dose descriptor:

LOAEL

Generation:

F1

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: suffered kidney damage

Remarks on result:

other: not specified

2

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

5 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No significant change in body & organ weight

Remarks on result:

other: not specified

Target system / organ toxicity (F1)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Treatment related:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Treatment related:

not specified

Relation to other toxic effects:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

The developmental and reproductive effects of Dibromoacetic acid (DBA) were evaluated in a one generation study on C57Bl/6J mice (7-17 mice/sex). DBA had shown a No adverse observed effect level (NOAEL) on 5 mg /kg/day, whereas the Low adverse observed effect level (LOAEL) was found to be 50 mg/kg/day based on kidney damage and increase in testis weight.

Executive summary:

To assess the developmental and reproductive effects of Dibromoacetic acid (DBA),C57Bl/6J mice (7-17 mice/sex) were orally administered with 0, 5 or 50 mg DBA/kg/day by drinking water for 3 and 7 weeks, respectively. The observations included significant increases in testis and liver weights in the highest dose group. High dose female mice at the same age also had increased liver and kidney weights. At seven weeks of age, males in the high dose group had decreased testis and kidney weights, while DBA does not appear to be detrimental to the gametogenic potential of mice at the dose levels tested.However, the No observed adverse effect level (NOAEL) was found to be 5mg /kg/day, whereas theLow observed adverse effect level (LOAEL) was 50 mg/kg/day,based on kidney damage and increase in testis weight