1,4-dichlorobutane

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Only male animals were used and histopathology was not carried out.

Data source

Reference

Reference Type:

publication

Title:

4-Week repeated oral dose toxicity study of 1,4-dichlorobutane in rats

Author:

Wook-Joon Yu

Year:

2013

Bibliographic source:

Lab Anim Res 2013: 29(1), 48-54

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

Only 6 male animals were used per group. No histopathological investigation of preserved organs was conducted.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS:
- Strain: Rat / Sprague-Dawley
- Number and sex: 24 males (6 per group)
- Breeder: Orient Bio (Seoul, Korea)
- Body weigth: mean 284 g at study start
- Age: 4 weeks
- Acclimatization period: 1 week

ENVIRONMENTAL CONDITIONS:
- Diet: commercial rodent chow (PMI Nutritional International Inc., Richmond, IN, USA) ad libitum
- Water: tab water ad libitum
- Housing: 2 animals per cage
- Temperature: 23°C ± 3°C
- Rel. Humidity: 50% ± 10%
- Light/dark period: 12/12h

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

4 weeks

Frequency of treatment:

once daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

300 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

6 males per dose

Control animals:

yes, concurrent vehicle

Details on study design:

The test article was administered once daily by gavage to male rats at dose levels of 0, 100, 300, and 1,000 mg/kg/day for 4 weeks. All rats were sacrificed at the end of the treatment period. During the test period, clinical signs, mortality, body weight, hematology, serum biochemistry, gross findings, and organ weight were examined.

Examinations

Observations and examinations performed and frequency:

All animals were observed twice daily for any clinical signs of toxicity and mortality. Furthermore, body weight was recorded at the beginning of the study and once per week during the period of administration.
Blood samples were taken at necropsy for the investigation of haematology and clinical chemistry parameters.

Sacrifice and pathology:

Animals were sacrificed by exsanguination from the abdominal aorta. Complete gross postmortem examinations were performed on all terminated animals. Absolute and relative organ weights were measured for brain, liver, spleen, heart, seminal vesicles, prostrate, kidneys, adrenal gland, testes, epidymides.
Histopathological investigations were not carried out.

Statistics:

Statistical analysis was performed by comparing the treatment groups with the control group using the Path/Tox System (version 4.2.2; Xybion Medical Systems Co., Cedar Knolls, NJ, USA) and SAS software version 9.1 (SAS Institute, Cary, NC, USA) using Bartlett's test, ANOVA, Kruskal-Wallis non-parametric ANOVA Dunnett’s post-hoc test and Fisher's exact probability test.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

1000 mg/kg goup: salivation, decreased locomotor activity, loss of fur, abnormal fur, and closed eyes (6/6)
100 and 300 mg/kg groups: post-dose salivation (5/6, 6/6)

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In the high-dose group, body weight gain was significantly reduced compared to controls.

Food consumption and compound intake (if feeding study):

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

100 mg/kg: significant increase in AST compared to controls (not treatment-related, no dose-dependency)
300 mg/kg: no significant changes
1000 mg/kg/day: significant increase in ALT, ALP, T-CHO, T-BIL, ALB, PL, BUN, and GGT compared to controls (treatment-related)

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, treatment-related

Description (incidence and severity):

1000 mg/kg goup: decreased locomotor activity, closed eyes (6/6)

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

100 mg/kg: significant increase in relative weights of liver and kidney
300 mg/kg: significant increase in the absolute and relative weights of the liver and relative weight of the kidneys
1000 mg/kg: significant increase absolute and relative weights of the liver, the relative weights of the heart and kidneys, and significant decrease in the absolute weight of seminal vesicles

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Any other information on results incl. tables

The observed increased organ weights of the liver were dose-dependent starting in the lowest dose, although in the low-dose group the relative weight was increased significantly, only. The absolute liver weight was biologically increased but not yet statistically significant; the increase reached significancy in the mid-dose group.

Serum biochemical parameters related to liver toxicity were increased in parallel, but in the high-dose group only.

The organ weight increases in the kidney reached significancy in relative weights in all dose groups, however, the increase in absolute weights is on a similar level in all dose groups, which does not reach statistic significancy but a further dose-dependent increase is lacking. Serum biochemical parameters related to kidney toxicity were increased in the high-dose group.

Organ weight changes in heart and seminal vesicles can be attributed to decreased body weight the in high-dose group an are considered not to be teatment-related.

Combined findings of increased organ weights in liver and kidneys and elevated related serum biochemisty parameters indicate that liver and kidney are target organs of 1,4-dichlorbutane toxicity after repeated administration.

Applicant's summary and conclusion

Conclusions:

Following daily oral administration of 1,4-dichlorbutane to rats, it can be concluded that under the conditions of this test the target organs of 1,4-dichlorbutane in rats are liver and kidney characterised by organ weight increases at all dose groups and elevated related serum biochemical parameters at the highest dose group. However, since no histopathological investigations have been conducted, the NOAEL cannot be determined.
As a conclusion, based on the results of this study it cannot be determined if a classification of 1,4-dichlorbutane for specific organ toxicity according to Regulation (EC) 1272/2008 is warranted.