3-chloropropene

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: - no guideline followed - non-GLP - very limited information on experimental details

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1985

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Thirty one TO albino, mice, 3-4 months old and weighing 30-40 g were dosed by gastric intubation 3 times weekly with 3-chloropropene at dosages of 300 or 500 mg/kg (BDH, wt per ml at 20° C, 0.930-0.940 g, in concentrations of 6% or 10%, dissolved in arachis oil) for periods from 2-17.
- Nine control mice were fed with 0.2 ml arachis oil 3 times weekly for up to 17 weeks. Animals were killed after various periods of regular dosing by perfusion fixation through the aorta under deep pentobarbitone sodium anaesthesia.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3-chloropropene

EC Number:

203-457-6

EC Name:

3-chloropropene

Cas Number:

107-05-1

Molecular formula:

C3H5Cl

IUPAC Name:

3-chloroprop-1-ene

Details on test material:

No information was given about the test material, but as in the publication some of the results of LU 1982 were repeated and as there is an intersection in the two lists of authors it was concluded by the reviewer that they probably used the same material and therefore the information from Lu 1982 is presented here:
- Name of test material (as cited in study report): allyl chloride - Physical state: colorless liquid
- Analytical purity: either twice distilled (>99 %) or of a commercial grade with a purity of about 90%,
probably in the study presented her the 99 % pure substance was used
the use of the 90 % substance in the acute experiments was explicitely reported
- Lot/batch No.: not reported
- Stability under test conditions: stable
- Storage condition of test material: not reported
Confidential details on test material

Test animals

Species:

other: TO albino mice

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

3-4 months old and weighing 30-40 g
no further data reported

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

gastric intubation 3 times weekly with 3-chloropropene at dosages of 300 or 500 mg/kg (BDH, wt per ml at 20° C, 0.930-0.940 g, in concentrations of 6% or 10%, dissolved in arachis oil)

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

Once per day, for 2 – 17 wks

Frequency of treatment:

3d/wk

Doses / concentrations

Remarks:

Doses / Concentrations:
300 and 500 mg/Kg bw
Basis:
other: nominal via gavage

No. of animals per sex per dose:

Unclear, 31 treated mice, 9 controls

Control animals:

yes, concurrent vehicle

Details on study design:

no data

Positive control:

no data

Examinations

Observations and examinations performed and frequency:

see below

Sacrifice and pathology:

- Animals were killed after various periods of regular dosing by perfusion fixation through the aorta under deep pentobarbitone sodium anaesthesia.
- For light microscopy, 3 functionally affected animals were perfused with formal calcium followed by FAM (1 part formaldehyde, 1 part acetic acid, 8 parts methanol). Paraffin sections were stained with H.E., haemotoxylin van Gieson, luxol fast blue/cresyl violet and Glee's and Marsland's silver impregnation. Two mice showing hind limb weakness were perfused with cold formal calcium, and serial frozen sections of gastronemius muscle and soleus muscle were stained to show end plate cholinesterase and nerve ending axons using the bromoindoxyl acetate-silver technique of Pestronk and Drachman (Pestronk A, Drachman DB. A new stain for quantitative measurement of sprouting at neuromuscular junction. Muscle and Nerve 1978; 1: 70-74.4.).
- For electron microscopy, the rest of mice were perfused with Kanovsky's fixative (3% glutaralde¬hyde, 1% paraformaldehyde in 0.07 M cacodylate buffer at PH 7.3). The nervous tissues were post fixed in 1% osmium tetroxide in sodium cacodylate buffer (pH 7.3). Semi-thin (1 micrometre) araldite sections were stained with 1% toluidine blue, and thin sections were treated with uranyl acetate and lead citrate.

Other examinations:

no

Statistics:

Not reported

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

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):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY
Mice showed weakness of hind limbs after being dosed with 3-chloropropene at 500 mg/Kg for about 1 month.

BODY WEIGHT AND WEIGHT GAIN
no data

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
no data

FOOD EFFICIENCY
no data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
no data

OPHTHALMOSCOPIC EXAMINATION
no data

HAEMATOLOGY
no data

CLINICAL CHEMISTRY
no data

URINALYSIS
no data

NEUROBEHAVIOUR
see above, under clinical signs

ORGAN WEIGHTS
no data

GROSS PATHOLOGY
no data

HISTOPATHOLOGY: NON-NEOPLASTIC
Light microscopy:
- Teased nerves showed some fibres undergoing Wallerian degeneration
- Early changes were most readily found, however, in animals dosed for the shortest time (13 days); these changes included increased density of staining of the axon, or apparent loss of the axon with or without myelin sheath degeneration
- Degenerating fibres(irregular clumps of myelin and accompanying axonal changes) generally in intramuscular nerve bundles, and in the small nerve to the medial head of the gastronemius muscle; seldomly in the rural nerve and sometimes in sciatic, median and ulnar nerves and also in the ventral roots
- Some degenerating fibres were seen in the white matter in ventral, dorsolateral and dorsal columns grey matter of the anterior horn, and in some mice there were bilateral lesions consisting of degenerated astrocytes and swollen astrocytic process
- atrophied muscle fibres in the grastronemius muscle was a relatively consistent feature in most treated animals from 23 days of dosing indicating neurogenic atrophy
- female mice showed fewer changes than males.
- few chains of sarcolemmal nuclei in longitudinal sections of leg and foot muscles and some beaded preterminal axon showed a number of stained endplates without associated axons. Axonal sprouting was seen at a few endplates
Electron microscopy:
- densely staining axons seen in 1 micrometre sections were often found to contain accumulations of neurofilaments and to contain aggregations of degenerated mitochondria.
- loss of axons was due to the dissolution of axonal contents. Later stages of degeneration were also evident with breadkdown of myelin sheaths, presence of macrophages containing myelin debris, and occasional Schwann tubes containing one or more Schwann cells
- Abnormalities of Schwann cell cytoplasm, indicating direct effect of allyl chloride upon these cells
- Swollen axons and remnants of basement membranes in unmyelinated fibres were seen in animals dosed for short periods, and collagen pockets were seen frequently. Quantitative studies of unmyelinated fibres showed a reduction in their numbers in allyl chloride treated mice.
- Marked swelling and degenerative changes of some astrocytes in the ventral horn region of spinal cord were seen. Some neurons showed peripheral vacuolation, apparently originating from swelling of the Golgi apparatus. Atrophied muscle fibres with redundant basement membranes and numerous end-plates with complete loss of associated axon terminals were found in gastronemius muscles. Axonal sprouting was seen near the denervated end-plates.


HISTOPATHOLOGY: NEOPLASTIC (if applicable)
no data

HISTORICAL CONTROL DATA (if applicable)
no data

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Executive summary:

In the present study (He 1985) thirty one TO albino, mice, 3-4 months old and weighing 30-40 g were dosed by gastric intubation 3 times weekly with 3-chloropropene at dosages of 300 or 500 mg/kg (BDH, wt per ml at 20° C, 0.930-0.940 g, in concentrations of 6% or 10%, dissolved in arachis oil) for periods from 2-17 weeks. Nine control mice were fed with 0.2 ml arachis oil 3 times weekly for up to 17 weeks. Animals were killed after various periods of regular dosing by perfusion fixation through the aorta under deep pentobarbitone sodium anaesthesia. Goal of the study was to determine the neurotoxic effects of 3-chloropropene after repeated subchronic exposure via the oral route.

Early changes of Wallerian degeneration appeared concurrently at many levels, e.g. in the grey matter of ventral horn, ventral roots, sciatic nerves and terminal parts of motor nerves, but a higher proportion of fibres was affected in the more distal parts.

Electron microscopically, loss of unmyelinated fibres is an early feature of 3 -chloropropene intoxication and has been confirmed by quantitative studies. An increase in the number of axonal neurofilaments appears to be a specific change preceding the onset of Wallerian degeneration in myelinated fibres. There was no significant evidence of neuronal degeneration in the 3 -chloropropene treated mice, but neurons within the ventral horn and a few sensory ganglion cells showed some abnormalities perhaps reflecting a metabolic disturbance. Schwann cells appear to be affected by 3 -chloropropene directly, since alterations were found in the cytoplasm apparently independent of any axonal degeneration. However, there was no segmental or paranodal demyelination seen in teased nerve fibres.

Some nerve fibre degeneration was found in the dorsal column and dorsal lateral column of the spinal cord at cervical levels, suggesting a distal degeneration of the centrally directed fibres of the dorsal root ganglion cells. This topography of the degeneration points to a primary axonal effect which generally falls into the pattern of a central-peripheral distal axonopathy as described by Spencer and Schaumberg (Spencer PS, Schaumberg HH. Central-peripheral distal axonopathy. The pathology of dying-back polyneuropathies. Progr Neuropathol 1976; 3: 253-295.).