3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP near-guideline study, acceptable for assessment.

Data source

Reference

Reference Type:

publication

Title:

Thirteen-week toxicity study of d-alpha-tocopheryl acetate (Vitamin E) in Fischer 344 rats.

Author:

Abdo KM, Rao G, Montgomery A

Year:

1986

Bibliographic source:

Fd Chem Toxic. 24 (10/11): 1043-1050.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

α-tocopheryl acetate

EC Number:

200-405-4

EC Name:

α-tocopheryl acetate

Cas Number:

58-95-7

Molecular formula:

C31H52O3

IUPAC Name:

2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-3,4-dihydro-2H-chromen-6-yl acetate

Details on test material:

Vitamin E acetate (d-alpha-tocopheryl acetate); according to the authors, purity was >99%

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratory, Kingston, NY
- Age at study initiation: 25 days
- Housing: stainless steel cages
- Diet: ad libitum, modified AIN-76 diet
- Water: ad libitum
- Acclimation period: 11 days

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

The vitamin (>99% pure and obtained from Eastman Kodak Company, Rochester, NY) was administered in corn oil by gavage at the rate of 3.5 ml/kg
body weight daily for up to 13 weeks.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
125, 500, 2000 mg/kg bw/d
Basis:

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

Two control groups (10 rats/sex/group) were either administered corn oil by gavage (vehicle control group) or remained untreated (untreated control group).
Post-exposure period: none

Positive control:

None

Examinations

Observations and examinations performed and frequency:

Individual blood samples (with or without heparin) for haematology and clinical chemistry determinations were collected by terminally bleeding ten males and ten females from each treatment group via the vena cava at days 5, 45 and 90 of dosing treatment.
Haematology determinations, which included mean corpuscular cell volume, haemoglobin, haematocrit, erythrocyte count and total and differential leucocyte counts, were made on a Baker 7000 cell counter (Baker Instruments, Allentown, PA) . Prothrombin time (PT) and activated partial thromboplastin time (APTT) were determined according to the Coag-a Mate operator's manual (General Diagnostics, Division of Warner-Lambert Co, Morris Plains, NJ) . Fibrinogen levels were determined according to the turbidimetric procedure of Exner using the Cetrifichem 400 (Exner, 1979). Serum samples were analysed for chloride, alkaline phosphatase, thyroxine (T4) and γ-glutamyl transpeptidase (GGT) using the Centrifichem 400 according to the procedures specified by the manufacturer (Baker Instruments, Allentown, PA). Triiodothyronine (T3) and thyroid-stimulating hormone (TSH) were determined by radioimmunoassay procedures (Kieffer, 1974) .

Sacrifice and pathology:

At the end of the treatment period, surviving animals were sacrificed and subjected to complete necropsy.
Organ weights and organ-to-body weight ratios were determined for brain, heart, kidneys, liver, spleen, thyroid and parathyroid (combined), thymus, pituitary gland, ovary, uterus, prostate, epididymis and testes.
In addition to these organs, the spinal cord, eyes, salivary gland, mammary gland, oesophagus, lungs with mainstem bronchi, trachea, stomach, small and large intestine, adrenals, pancreas, urinary bladder, mesenteric lymph node, bone marrow, sternum and sciatic nerve with skeletal muscle were
collected, fixed in 10% buffered formalin, embedded in paraffin, sectioned at 5 ,um and stained with haematoxylin and eosin. All tissues from the control and the high-dose groups were examined microscopically. For the lower-dose groups, only tissues that were designated as targets for vitamin E toxicity were examined (not further specified).

Statistics:

The significance of differences between Vitamin E-treated and control groups was assessed using the Dunnett's multiple comparison procedure. Dose-response trend was assessed by Jonckheere's test. Results were considered significant when the calculated P value was 0.05 or less.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

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:

effects observed, treatment-related

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

Seven out of 10 high dose males died during weeks 9-11.
The test substance had no effect on food consumption or body weights.
The relative liver weight was significantly increased in high dose females.
Administration of 2000 mg/kg bw/d caused hematological changes: prolongation of both prothrombin and activated partial thromboblastin (APTT) times, reticulocytosis and a decrease in hematocrit values and hemoglobin concentrations was observed in males; APTT times were also increased in females. Hemorrhagic diathesis was observed in males and females of the high dose group; and increased medullary erythropoiesis was seen in the spleen of one high dose male.
A compound-related increase was also observed in the plasma levels of thyroid-stimulating hormone. However, without a corresponding increase in T3 and T4, and no evidence for increased energy metabolism ( food consumption and body weights were comparable to control groups), the toxcicological relevance was doubted.

The test substance at all dose levels tested caused interstitial inflammation and adenomatous hyperplasia of the lung. The lung lesions were observed in all vitamin E-treated groups, and the incidence and severity increased in a dose-dependent manner. These lesions were characterized by increased cellularity, vascular congestion, thickened alveolar walls and the presence of foamy macrophages (some of which had undergone cell death and degeneration) in the alveolar spaces. A lipid-like yellow pigmentation was often present within either the macrophages or alveoli.
None of these lesions, however, were considered to reflect systemic toxic effects of the test or reference articles. The changes in the lungs were considered to be a local reaction to the aspiration of a-tocopheryl acetate into the lungs that would not occur under conditions of normal use.

Therefore, for the NOAEL derivation the effects in the lungs were not considered.
Because at 500 mg/kg only the APTT value is increased, but not the PT and fibrinogen values, the NOAEL is set at 500 mg/kg.

Effect levels

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified