4-fluoroaniline

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Neither guideline nor GLP compliant study but nevertheless well documented and scientifically acceptable.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2003

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

The test method is according to a neurotoxicity test. Based on a preliminary study a TDL0 of 600 mg/kg bw was determined which was used as application dose.

GLP compliance:

not specified

Test type:

fixed dose procedure

Test material

Test material information

Constituent 1

Reference substance name:

4-fluoroaniline

EC Number:

206-735-5

EC Name:

4-fluoroaniline

Cas Number:

371-40-4

Molecular formula:

C6H6FN

IUPAC Name:

4-fluoroaniline

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 4 weeks
- Housing: Polycarbonate cages (three rats per cage)
- Diet: standard laboratory diet (MF, Oriental Yeast Co., Ltd, Tokyo, Japan)
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20-24 °C
- Humidity: 40-70%
- Photoperiod: 12-h light/dark

Administration / exposure

Route of administration:

oral: unspecified

Vehicle:

olive oil

Doses:

600 mg/kg bw

No. of animals per sex per dose:

9 (males)

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 15 days
- Frequency of observations and weighing: All rats were carefully observed for mortality and clinical signs at 30 min and 5 h after dosing and once a day thereafter for the following 15 days. Body weights were recorded before dosing and on days 2, 4, 8, 15 and 16.
- Necropsy of survivors performed: Yes
- Other examinations performed:

- clinical signs:
Detailed clinical observations with functional tests were conducted on all rats 2 days before dosing and on day 9, and on all the surviving rats on day 15.
The observer first recorded each rat’s posture in the home cage, along with palpebral closure and the presence or absence of circling, writhing, biting, convulsions or vocalizations. Then the observer removed the rat, rating the ease of removal and handling, and recorded such signs as exophthalmos, crustiness around the eyes and piloerection. Extensor thrust, palpebral closure, fur appearance, lacrimation and salivation also were rated. The rat was placed on a field covered with a clean polypad. The rat was observed for 2 min and gait characteristics, arousal level and the number of supported or unsupported rearing and grooming episodes were recorded. At the end of 2 min, the number of faecal boluses and pools of urine on the field were recorded. Then the following reflex tests were carried out and recorded: approach response, touch response, finger-snap response, tail-pinch response, surface righting reflex and aerial righting reflex. Grip strength for fore- and hindlimbs was measured by a grip strength apparatus (Muromachi Kikai Co., Tokyo, Japan) and the mean value of two trials for each rat was recorded. Finally, the pads of the hind feet were painted with Indian ink and the rat was held in a horizontal position at a height of ca. 30 cm before being dropped onto paper. The distance between ink blots was measured and the mean value of two trials for each rat was recorded.

- histopathology:
Three rats from each experimental group were killed in numerical order on day 10 and the other rats were killed on day 16, under deep anaesthesia by an intraperitoneal injection of sodium pentobarbital. After cardiac perfusionfixation with a phosphate buffer solution containing paraformaldehyde (4%), glutaraldehyde (1%) and heparin (1000 IU/ L), the following organs and tissues were collected and fixed in 10% neutral buffered formalin solution: forebrain, including cerebral cortex, basal ganglia and corpus callosum; midbrain, including hippocampus, thalamus and hypothalamus; mesencephalon, including substantia nigria, colliculi, tectum and tegmentum; hindbrain, including cerebellum, pons and medulla oblongata; spinal cords, including cervical, thoracic and lumbar levels; trigeminal nerves with gasserian ganglia; and sciatic nerves. Tissues were processed for paraffin embedding, sectioned 5 μm thick, stained with haematoxylin and eosin (H&E) and examined by light microscopy.

Statistics:

The following data in all groups were analysed using multiple comparison tests: body weight, the number of faecal boluses and pools of urine on the open field, the number of grooming episodes and the number of supported or unsupported rearing events in the open field, data from the landing foot spray (cm) and the grip strength (g) for fore- and hindlimbs. They were first analysed by Bartlett’s test. If the group variance was determined to be homogeneous, all groups were compared by a one-way analysis of variance. If Bartlett’s test indicated heterogeneous variance, the Kruskal–Wallis test was employed and Dunnett’s test was used when there was a significant difference between the groups.
Results were expressed as the mean +/- standard deviation (SD). The other categorical and rank data obtained from the detailed clinical observations were analysed by the a × b chi-squared test, and when there was a significant difference Armitage’s chi-squared test was used to compare the difference between each halogenated aniline-treated group and the control group; P < 0.05 or P < 0.01 were considered significant for the statistical tests.

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LDLo

Effect level:

600 mg/kg bw

Based on:

test mat.

Mortality:

None

Clinical signs:

other: - cyanosis between days 1 and 4 - only one rat showed decreased movement on day 1 - reduced response to extensor thrust of the hindlimb was found in on days 9 and 15 - gait abnormalities, including ataxia or hindlimb paralysis, were also found on days 9 a

Other findings:

Histopathology:
- A spongy change in the white matter of the spinal cords was found
- The lesions arose symmetrically and they were prominent in the lateral and ventral funiculi of the white matter. The lesions in the thoracic level were most prominent throughout the spinal cord. A spongy change in the tegmentum of the mesencephalon or the spinocellebelar tracts of the pons and medulla oblongata, and nerve fibre degeneration in the spinal nerves, trigeminal nerves, or sciatic nerves were also found.

Applicant's summary and conclusion

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information