1,6-diiodoperfluorohexane

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1997 ?

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Only the results (mean group data) are available (translation from a report in Japanese). The material and methods information was not available.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

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:

not specified

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,6-diiodoperfluorohexane

EC Number:

206-794-7

EC Name:

1,6-diiodoperfluorohexane

Cas Number:

375-80-4

Molecular formula:

C6F12I2

IUPAC Name:

1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoro-1,6-diiodohexane

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): C6-diiodide
- Substance type: monoconstituent

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
No data available

ENVIRONMENTAL CONDITIONS
No data available

IN-LIFE DATES: No data available

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

not specified

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
No data available

VEHICLE
No data available

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

28 days

Frequency of treatment:

Daily

Doses / concentrations

Remarks:

Doses / Concentrations:
1, 3, 10, and 20 mg/kg
Basis:

No. of animals per sex per dose:

6 per sex and per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale, rationale for animal assignment: no data available
- Rationale for selecting satellite groups: the satellite groups were daily administered the test item at 10 or 20 mg/kg bw for 28 days.
- Post-exposure recovery period in satellite groups: 14 days
- Section schedule rationale: no data available

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule, cage side observations checked: no data available

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: no data available

BODY WEIGHT: Yes
- Time schedule for examinations: once on the day prior to the start of the administration; once on the first day of administration and then once every 2-3 days during the administration period (28 days) for all treated groups; and once on the first day of recovery and then once every 2-3 days during the recovery periods (14 days) for the control, 10-mg/kg and 20-mg/kg groups

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes; once on the first day of administration and then once every 3-4 days during the administration period (28 days) for all treated groups; and once on the fourth day of recovery and then once every 3-4 days during the recovery periods (14 days) for the control, 10-mg/kg and 20-mg/kg groups
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION AND COMPOUND INTAKE: No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood, anaesthetic used for blood collection, animals fasted, how many animals: no data available
- Parameters checked: red blood cells (RBC), white blood cells (WBC), haemoglobin (Hb), haematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), platelet count, reticulocyte count, coagulation (prothrombin time (PT), activated partial thromboplastin time (APTT)), differential leukocyte count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood, animals fasted, how many animals: no data available
- Parameters checked: glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP), cholinesterase (ChE), gamma-glutamyl transpeptidase (γ-GTP), total cholesterol (T-Cho), triglycerides (TG), glucose, total protein, albumin, globulin, albumin/globulin ratio, blood urea nitrogen (BUN), creatinine, total bilirubin (T-Bil), calcium (Ca), inorganic phosphorus (IP), sodium (Na), potassium (K), chloride (Cl).

URINALYSIS: Yes
- Time schedule for collection of urine, metabolism cages used for collection of urine, animals fasted: no data available
- Parameters checked: volume, colour, pH, protein, ketones, bilirubin, occult blood, glucose, urobilinogen

NEUROBEHAVIOURAL EXAMINATION: No data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
Adrenal glands
Brain
Cecum
Colon
Duodenum
Epididymides
Heart
Hypophysis
Ileum
Incisors
Jejunum
Kidneys
Liver
Lymph nodes - mesenteric
Mammary gland
Oral cavity
Ovary
Pituitary gland
Prostate
Rectum
Seminal vesicles
Skin
Spleen
Stomach - forestomach, glandular stomach
Testis
Thymus
Thyroid gland
Uterus
Vagina
All gross lesions

Other examinations:

ORGAN WEIGHTS (absolute and relative):
Adrenal glands
Brain
Epididymides
Hypophysis
Kidney
Liver
Ovary
Prostate
Seminal vesicle
Spleen
Testis
Thymus
Thyroid gland
Uterus

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Mortality:

mortality observed, treatment-related

Description (incidence):

see in "Details on results"

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

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

Description (incidence and severity):

see in "Details on results"

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

see in "Details on results"

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY (Table 1 in "Any other information on results incl. tables")
The administration of the test item caused no death during the administration period. Further, signs of neurosis were noted in a preliminary test.
Salivation was seen in almost all male and female rats from vehicle control and treated groups, regardless of the dose level administered. Although this clinical sign was observed in control animals, it was considered to be the effect of the test substance. This effect was not observed during the recovery period.
Some clinical signs were described in few animals treated with the test item, regardless of the dose level: e.g., alopecia, coarse and hard coat of hair, dirt around the anus and the hypogastric region, emaciation; all these effects remained in rare animals of both genders during the recovery period.
Fallen spontaneous movement was mainly seen in males and females rats treated with the dose levels of 10 and 20 mg/kg bw/day and it was still observed during the recovery period in the major part of treated animals. 
New clinical signs appeared in few animals of both sexes during the recovery period: e.g., whitening of the tails, scab formation.

BODY WEIGHT AND WEIGHT GAIN (Table 2 in "Any other information on results incl. tables")
During the administration period, males and females treated with dose levels equal or higher than 3 mg/kg bw/day showed either reduced body weight or inhibited body weight gain. Moreover, males and females treated with a dose of 1 mg/kg bw/day displayed an inhibited body weight gain or such a tendency. Although a tendency towards recovery was noted in males and females treated with dose levels of 10 or 20 mg/kg bw/day, yet the low body weights remained during the recovery period.

FOOD CONSUMPTION AND COMPOUND INTAKE (Table 2 in "Any other information on results incl. tables")
During the administration period, animals treated with dose levels equal or higher than 3 mg/kg bw/day showed reduced food consumption. Although a tendency towards recovery was noted in animals treated with dose levels of 10 or 20 mg/kg bw/day, yet the low feeding amount remained in males while an increase in feeding amount was observed in females treated with dose level of 20 mg/kg bw/day.

HAEMATOLOGY (Table 3 in "Any other information on results incl. tables")
At the end of the administration period, almost all significant haematological impairments were seen at a dose level equal and/or higher than 3 mg/kg bw/day: decrease in red blood cell (RBC) number in all females; decrease in white blood cell (WBC) number, haemoglobin (Hb) and haematocrit (Ht) concentration, average volume of red blood cells (MCV), average amount of red blood cell haemoglobin (MCH) in all treated males and females; prolonged prothrombin time (PT) and prolonged time of the activated portion of thromboplastin (APTT) in males and females. 
The average density of red blood cell haemoglobin (MCHC) was mainly decreased in females treated with the test item. Similarly, only females treated with 10 or 20 mg/kg bw/day displayed a decrease in lymphocyte and monocyte percentages and an increase in neutrophil percentage in the segmentation nucleus. 
During the recovery period, the major part of the haematological changes abovementioned remained: e.g., prolonged time of APTT and decreased MCH in males; MCV decrease in females; decrease in WBC number, Hb and Ht concentration, MCHC, lymphocyte percentages in males and females. In addition, new haematological changes appeared in animals of both sexes during the recovery period: i.e., increase in reticulocyte percentage.
All these changes were considered to be caused by the influence of the test substance.

CLINICAL CHEMISTRY (Table 4 in "Remarks on results including tables and figures")
Regardless of the dose level administered, all males and females displayed a decrease in total cholesterol and albumin/globulin ratio at the end of the administration period. Moreover, from the dose level of 3 mg/kg bw/day and/or above, animals of both sexes showed an increase in total protein, gamma-GTP, total bilirubin, and GPT. Furthermore, at the end of the administration period, increased BUN and decreased inorganic phosphorus levels were seen in males at 10 and 20 mg/kg bw/day; while decreased ChE and chloride levels and increased potassium levels were measured in females at 10 and/or 20 mg/kg bw/day.
During the recovery period, some biochemistry changes remained: increased GPT in males; decreased ChE and increased gamma-GTP in males and females. In addition, new biochemistry changes appeared in males and females during the recovery period: decrease in creatinine in males and females; decrease in inorganic phosphorus and increase in TG, sodium and calcium in females. 
All these changes were considered to be caused by the influence of the test substance.

URINALYSIS
Uroscopy showed a tendency towards increased albumin in urine in males treated with 10 mg/kg bw/day and more and females treated with a dose level of 20 mg/kg bw/day. At the end of the period of recovery various changes were found to remain.

ORGAN WEIGHT (Table 5 in "Remarks on results including tables and figures")
After 28 days of treatment, the weight of various organs was significantly altered in treated animals of both sexes. When expressed as organ/body weight ratio, the weight of thymus, prostate, seminal vesicles, epididymis, and testes significantly decreased in treated males, while the weight of brain, liver, kidneys, adrenals, hypophysis, and thyroid significantly increased in the same treated groups. Overall, treated females displayed significant decreases in thymus weight and significant increases in brain, liver, kidney, thyroid, hypophysis, and uterus weights (i.e., when expressed as organ/body weight ratio). 
After 14 days of recovery, the relative weight of almost all organs abovementioned remained significantly altered. When expressed as organ/body weight ratio, epididymis, prostate, seminal vesicles and testes weights were still significantly decreased, and the weight of spleen, liver, kidney, brain, thyroid, hypophysis, lungs, thymus, and adrenals significantly increased in males at the end of the recovery period. In females, the weight of brain, adrenals, spleen, liver, kidney, hypophysis weights was still increased and the decrease in thymus relative weight remained. 
All these changes were considered to be caused by the influence of the test substance.

GROSS PATHOLOGY (Table 6 in "Attached background material")
After 28 days of administration, the main gross lesions observed were localised in the liver from males and females of groups treated with 3, 10 and 20 mg/kg bw/day (i.e., accentuated lobular pattern with whitish margin and enlargement). Furthermore, a reduction in thymus size and whitish spots in mesenteric lymph nodes were also seen in all animals treated with dose levels of 10 and/or 20 mg/kg bw/day. In addition, all treated males from dose groups 3, 10 and 20 mg/kg bw/day showed a size reduction of testes, epididymis, prostate and seminal vesicles. A smaller seminal vesicle and prostate was also noticed in 3 males from the group administered 1 mg/kg bw/day.
After 14 days of recovery, males still showed hepatic lesions and size reduction of testes, epididymis, prostate and seminal vesicles, regardless of the dose level. Gross lesions in the liver remained in all females treated with the dose levels of 10 and/or 20 mg/kg bw/day.

HISTOPATHOLOGY: NON-NEOPLASTIC (Table 6 in "Attached background material")
After 28 days of treatment, hepatic, spleen, renal, and thymus lesions were seen in males and females treated with the test item, notably at the dose levels of 10 and 20 mg/kg bw/day (e.g., swollen hepatic cells, hemosiderin deposition in the spleen, atrophy of thymus). Moreover, atrophy of seminal vesicles, testes, epididymis, and prostate, and congestion of lymph nodes was observed in all males from the dose level of 3 mg/kg bw/day. In addition, histopathological lesions of ovaries, uterus, vagina and mammary glands were described in all females exposed to the test substance, regardless of the dose level (i.e., decreased copora lutea and increased follicular cyst in ovaries, tall columnar epithelial cells in uterus, mucification in vagina, hyperplasia of mammary glands).  
After the 14-day recovery period, the findings in liver, spleen, kidneys, ovaries, mammary glands, and male reproductive organs were still present.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

< 1 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

2

Dose descriptor:

LOAEL

Effect level:

1 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1: Significant clinical signs after 28-day treatment and 14-day recovery

Gender

After 28-day treatment

After 14-day recovery

Males

Females

Males

Females

Dose (mg/kg bw/day)

0

1

3

10

20

0

1

3

10

20

0

10

20

0

10

20

Salivation

9/12

6/6

6/6

12/12

12/12

8/12

6/6

6/6

12/12

12/12

0/6

0/6

0/6

0/6

0/6

0/6

Decreas. spontan. locomotion

0/12

0/6

3/6

12/12

12/12

0/12

0/6

1/6

12/12

12/12

0/6

1/6

4/6

0/6

3/6

4/6

Decreas. respirat. rate

0/12

0/6

0/6

0/12

3/12

0/12

0/6

0/6

0/12

3/12

0/6

0/6

0/6

0/6

0/6

0/6

Emaciation

0/12

0/6

0/6

2/12

1/12

0/12

0/6

0/6

4/12

1/12

0/6

0/6

0/6

0/6

1/6

1/6

Unkempt hair

0/12

0/6

1/6

3/12

3/12

0/12

2/6

0/6

1/12

2/12

0/6

0/6

2/6

0/6

1/6

1/6

Loss and discolour. up. incisor

-

-

-

-

-

0/12

0/6

0/6

0/12

1/12

-

-

-

0/6

0/6

0/6

Loss and discolour. low. incisor

-

-

-

-

-

0/12

0/6

0/6

0/12

1/12

-

-

-

0/6

0/6

2/6

Staining around nose and mouth

0/12

3/6

2/6

4/12

5/12

0/12

3/6

3/6

2/12

2/12

0/6

0/6

0/6

0/6

0/6

0/6

Staining hair

-

-

-

-

-

0/12

2/6

0/6

0/12

0/12

-

-

-

0/6

0/6

0/6

Staining lower abdomen

0/12

0/6

0/6

0/12

2/12

0/12

0/6

1/6

1/12

1/12

0/6

0/6

1/6

0/6

0/6

0/6

Staining around anus

0/12

0/6

2/6

0/12

1/12

0/12

0/6

2/6

1/12

0/12

0/6

0/6

0/6

0/6

1/6

0/6

Soft stool

0/12

0/6

0/6

2/12

3/12

0/12

0/6

0/6

4/12

7/12

0/6

0/6

0/6

0/6

0/6

0/6

Loss of hair

0/12

2/6

0/6

1/12

4/12

0/12

1/6

1/6

1/12

3/12

0/6

1/6

3/6

0/6

1/6

0/6

 

Table 2: Body weight and food consumption after 28-day treatment and 14-day recovery

Gender	After 28-day treatment										After 14-day recovery
	Males					Females					Males			Females
Dose (mg/kg bw/day)	0	1	3	10	20	0	1	3	10	20	0	10	20	0	10	20
Body weight (g)	344.2	302.0*	193.5*	157.6*	157.8*	210.7	190.5	161.4*	138.0*	135.8*	412.3	208.7*	193.2*	228.5	174.3*	175.1*
Food consumption (g/rat/day)	19.4	19.7	10.0*	7.7*	8.1*	12.8	11.1	8.3*	7.0*	6.7*	27.2	19.6*	18.6*	17.7	16.7	21.2*

* = statistically significant

 

Table 3: Summary of significant haematology results after 28-day treatment and 14-day recovery

Gender	After 28-day treatment										After 14-day recovery
	Males					Females					Males			Females
Dose (mg/kg bw/day)	0	1	3	10	20	0	1	3	10	20	0	10	20	0	10	20
RBC (x 10^4/mm^3)	747	741	714	690	704	776	775	716*	682*	680*	789	686*	660*	794	714*	688*
WBC (x10²/mm^3)	101	95	66*	57*	57*	111	99	60*	58*	67*	132	67*	69*	103	53*	55*
Hb (g/dL)	14.7	14.4	13.5*	12.2*	12.5*	15.7	14.9	13.3*	12.4*	12.2*	15.3	12.7*	11.8*	15.1	13.5*	12.9*
Ht (%)	42.3	42.4	38.9*	36.2*	36.6*	43.9	43.0	39.2*	36.4*	35.8*	43.3	37.2*	34.5*	42.1	39.8	38.7*
MCV (µm^3)	56.8	57.2	54.5	52.5*	52.1*	56.6	55.5	54.8	53.3*	52.7*	54.9	54.2	52.4	53.0	55.7*	56.3*
MCH (pg)	19.8	19.5	19.0	17.7*	17.8*	20.3	19.2*	18.7*	18.2*	18.0*	19.4	18.5	17.9*	19.0	18.9	18.7
MCHC (%)	34.9	34.0	34.8	33.8*	34.3	35.8	34.6*	34.0*	34.1*	34.1*	35.4	34.1*	34.2*	35.7	33.9*	33.3*
Reticulo (%)	27	21	20	25	18	24	25	25	21	22	26	76*	48	24	56*	72*
PT (sec)	11.5	12.3	12.0	12.9*	12.3*	11.5	12.3	12.4	12.4	13.0*	12.2	11.5	11.7	11.7	11.4	11.5
APTT (sec)	22.3	31.5*	31.6*	29.5*	27.8	20.7	28.4*	29.6*	31.3*	27.4*	23.8	17.9*	18.3*	19.7	18.6	19.8
Leukocyte N-seg (%)	17.7	16.1	20.7	25.2	25.0	9.9	13.3	17.8	25.9*	22.8*	12.3	25.5*	31.7*	14.1	28.8*	29.7*
Lymph	80.8	83.3	78.3	74.2	73.8	88.7	85.4	81.6	73.4*	76.7*	86.8	73.3*	67.0*	85.2	69.2*	68.7*
Mono	0.3	0.1	0.3	0.3	0.3	0.5	0.3	0.2	0.0*	0.0*	0.1	0.2	0.2	0.0	0.1	0.3

* = statistically significant

Applicant's summary and conclusion

Conclusions:

Based on the results of this study, a no-observed-effect-level (NOEL) was estimated to be under 1 mg/kg bw/day for the test substance.
Target organs identified from the dose level of 1 mg/kg bw/day were the liver, kidneys and reproductive organs.

Executive summary:

The purpose of this 28-day oral toxicity study was to evaluate the range of toxicity and to indicate potential target organs associated with the exposure of the test substance when administered to rats by gavage daily for 28 days. In order to assess the reversibility of any treatment-related findings, satellite groups of animals were maintained for a subsequent recovery period of 14 days without treatment.

 

Groups of 6 male and 6 female Sprague-Dawley rats were exposed to the test substance at dose levels of 0 vehicle control), 1, 3, 10, and 20 mg/kg body weight (bw)/day. Additional satellite groups of 6 males and 6 females were treated with dose levels of 10 and 20 mg/kg bw/day for 28 days and then kept for a 14-day period to investigate the potential for recovery. Mortality, clinical signs, body weight, food consumption, water consumption, ophthalmoscopic examinations, clinical laboratory investigations, organ weights, macroscopic and microscopic findings were recorded.

 

There was no case of death caused by the administration of the test substance during the entire administration period. Abnormal symptoms, decreases or inhibition in body weight gain and low values of feed consumption were found among the groups exposed daily to the test substance.

 

Further, males and females administered with 1 mg/kg bw/day test substance or more developed organ lesions in the liver, spleen and reproductive organ during the administration period. From the dose level of 1 mg/kg bw/day, almost all of the changes found through the clinical biochemistry and haematological examinations were considered to have been caused by hepato-bile duct troubles and renal impairments. The haematological examinations showed evidence of anaemia and lymphocytic alterations and further revealed changes in the mammary glands, mesenteric glands and spleen. Moreover, the remarkable impact on the reproductive organs and teeth, that is, changes (including relative organ weight and histopathological findings) in testes, epididymis, seminal vesicles and prostate glands in case of males and changes in ovary, uterus, vagina and mammary glands in case of females, were considered as specific changes caused by the test substance, besides the changes in the pituitary glands/hypophysis depending on the dose administered.

 

Following the recovery period, abnormal symptoms and abnormality in body weight and food consumption remained. Moreover, at the end of the recovery period various changes were still found in the clinical biochemistry and haematological examinations, uroscopy analysis, through measurement of organ weights and in the pathological inspection.

  

Based on the results of this study, the no-observed-effect-level (NOEL) was estimated to be below 1 mg/kg bw/day. Target organs identified from the dose level of 1 mg/kg bw/day were the liver, spleen and reproductive organs.