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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Data is from peer-reviewed journal

Data source

Reference
Reference Type:
publication
Title:
Preliminary screening for the potential of drinking water disinfection byproducts to alter male reproduction.
Author:
Gary R. Klinefelter’, Juan D. Suarez, Naomi L. Roberts, And Anthony B. Deangelo
Year:
1995
Bibliographic source:
Reproductive Toxicology, Vol. 9, No. 6. pp. 571-578, 1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
The reproductive effect of Chloral hydrate was evaluated in F344 male rats when administered orally in a one-generation.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
- Name of test material (as cited in study report): Chloral Hydrate
- Molecular formula (if other than submission substance): C2 H3C13O2
- Molecular weight (if other than submission substance): 165.403 g/mol
- Smiles notation (if other than submission substance):C(C(O)O)(Cl)(Cl)Cl
- InChl (if other than submission substance):1S/C2H3Cl3O2/c3-2(4,5)1(6)7/h1,6-7H
- Substance type: Organic
- Physical state: crystalline

Test animals

Species:
rat
Strain:
Fischer 344
Sex:
male
Details on test animals and environmental conditions:
- Source: Charles River Laboratories (Portage, MI)
- Age at study initiation: (P) x wks= 28 days of age
-Weight at study initiation: (P) Males: No data available
- Fasting period before study: No data available
- Housing: Animals were housed two per cage (20 x 25 x 47 cm) with laboratory grade pine shavings as bedding.
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet (e.g. ad libitum): Purina Laboratory Chow ad libitum
- Water (e.g. ad libitum): Water ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 °C
- Humidity (%):40 to 60%
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): 12 Light : 12 Dark, lights out at 1900 h
IN-LIFE DATES: From: To: No data available

Administration / exposure

Route of administration:
oral: drinking water
Type of inhalation exposure (if applicable):
not specified
Vehicle:
other: Deionized water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Dose were Prepared by dissolving 0.5 g/L CH, and 2.0 g/L Chloral hydrate (CH) in deionized water which is equivalent to 55.0 and 188.0 mg/kg.

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): vehicle used was deionized water
- Concentration in vehicle: 0.5 g/L and 2.0 g/L (i.e 55 mg/kg and 188 mg/kg resptively)
- Amount of vehicle (if gavage): No data available
- Lot/batch no. (if required): No data available
- Purity: No data available
Details on mating procedure:
- Any other deviations from standard protocol: Only male reproductive function was analysis in this study.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Samples of the bottled drinking water solutions were analyzed GC analysis monthly.
Analyses revealed that average actual concentrations were 0.78 g/L and 2.7 g/L for the CH exposures.
Duration of treatment / exposure:
52 week
Frequency of treatment:
Daily
Details on study schedule:
No data available
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 55 and 188 mg/kg
Basis:
no data
No. of animals per sex per dose:
Total: 18
0 mg/kg/day: 6 male
55.0 mg/kg/day: 6 male
188.0 mg/kg/day: 6 male
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: No data available
- Rationale for animal assignment (if not random): random
- Other: The rats used in this study were part of two different chronic cancer bioassay studies that were initiated in consecutive years. The sperm samples collected from each study were obtained at an interim (52 week) necropsy.
Water consumption and body weights were recorded weekly during the first month of exposure and then monthly afterward.

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: No
- Time schedule: No data available

BODY WEIGHT: Yes
- Time schedule for examinations: weekly for first month and then monthly

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

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: weekly for first month and then monthly

OTHER: At necropsy, the body, kidney, liver, spleen, and thyroid were weighed. all organs were examined for gross lesions, including discolorations, surface irregularities, nodular changes, and tumor masses. The left testis and epididymis were removed along with the liver, spleen, kidney, thyroid, stomach, intestine, and bladder for routine histopathologic analysis.

Computer-assisted motion analysis of cauda epididymal sperm, together with testicular and epididymal histopathology, as a preliminary screening for the potential of chloral hydrate to alter male reproductive function was performed.
Oestrous cyclicity (parental animals):
No data available
Sperm parameters (parental animals):
Percentage of motile sperm, percentage of progressively motile sperm, epididymal sperm motion and straight-line velocity, average path velocity and curvilinear velocity of sperm were examined.
Litter observations:
No data available
Postmortem examinations (parental animals):
Organ weight, Gross abnormalities and histopathology of male rat were examined
Organ weighted: Kidney, liver, spleen and thyroid gland
Organ examined:
Discolorations, surface irregularities, nodular changes and tumor masses. The left testis and epididymis, liver, spleen, kidney, thyroid, stomach, intestine and urinary bladder were examined
Postmortem examinations (offspring):
No data available
Statistics:
Statistical analysis were performed by using General Linear Model for motility parameters; percent motile, percent progressively motile, straight-line velocity, curvilinear velocity, path velocity, and linear index.

When significant differences (P < 0.05) were found in the overall ANOVA, the least-square means were compared to determine differences between the vehicle and CH-treatment groups.

An ANOVA also was used to analyze the number of sperm with a straight-line velocity less than 60 pm/s in the vehicle and 188 mgikg CH groups to determine significant treatment effects. The analysis was adjusted for differences in the number of motile sperm per treatment group.
Reproductive indices:
Linear index of sperm were examined.
Offspring viability indices:
No data available

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:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
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:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not specified
Other effects:
not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not specified
Reproductive function: sperm measures:
effects observed, treatment-related
Reproductive performance:
not specified

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS):No sign of toxicity were observed in treated rat as compared to control.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS):No significantly different were observed in body weight of treated rat as compared to control.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS):From water comsumption 55 mg/kg and 188 mg/kg of dose for Chloral hydrate CH were determine.


REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS):No data available

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS):When treated with 188.0 mg/kg/day significant decreased were observed in percentage of motile sperm (MOT) and percentage of progressively motile sperm (PMOT) were observed.

Mean straight-line velocities average path and straight-line velocity distributions were shifted to a lower modal velocity range as compared to control in 188 mg/kg/day .

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS):No data available

ORGAN WEIGHTS (PARENTAL ANIMALS):No significant change were observed in organ weight of treated rat as compared to control.

GROSS PATHOLOGY (PARENTAL ANIMALS):No gross lesions were observed in treated rat as copmared to control.

HISTOPATHOLOGY (PARENTAL ANIMALS):No evidences of perturbations in testicular histology such as seminiferous tubule atrophy, sloughed germ cells, or the presence of residual bodies in the lumen of the seminiferous tubule and no testicular or epididymal cells were observed in the lumen of the epididymis and there was no indication of an inflammatory response or granuloma formation were observed in treated rat as comapred to control.

Effect levels (P0)

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
55 mg/kg bw/day
Based on:
test mat.
Sex:
male
Basis for effect level:
reproductive function (sperm measures)
Dose descriptor:
LOAEL
Effect level:
188 other: mg/kg/day
Based on:
test mat.
Sex:
male
Basis for effect level:
reproductive function (sperm measures)

Target system / organ toxicity (P0)

Critical effects observed:
no

Results: F1 generation

General toxicity (F1)

Histopathological findings:
not specified

Details on results (F1)

No details available

Effect levels (F1)

Remarks on result:
other: not specified

Target system / organ toxicity (F1)

Critical effects observed:
not specified

Overall reproductive toxicity

Reproductive effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
NOAEL was considered to be 55.0 mg/kg bw/day while LOAEL was determined to be 188.0 mg/kg/day on the basis of effects in percentage of motile sperm (MOT) and percentage of progressively motile sperm (PMOT) when F344 male rats were exposed to chloral hydrate for 52 weeks.
Executive summary:

In a reproductive toxicity study, F344 male rat were exposed to chloral hydratein the concentration of 0, 55.0 and 188.0 mg/kg/day by oral drinking water for 52 weeks.

No significant effect were observed on clinical sign, body weight, organ weight, gross pathology and histopathology but significant decrease were observed in percentage of motile sperm (MOT) and percentage of progressively motile sperm (PMOT). In addition, Mean straight-line velocities average path and straight-line velocity distributions were shifted to a lower modal velocity range in 188.0 mg/kg/day treated rat as compared to control.

Therefore, NOAEL was considered to be 55.0 mg/kg bw/day while LOAEL was determined to be 188.0 mg/kg/day on the basis of effects in percentage of motile sperm (MOT) and percentage of progressively motile sperm (PMOT) when F344 male rats were exposed to chloral hydrate for 52 weeks.