Indium trichloride

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

A sub chronic toxicity and male and female fertility study conducted in Swiss mice was designed to assess the effects of indium chloride on male and female gametogenesis, female cyclicity, fertilization and implantation (Chapin et al., 1995). Female Swiss mice (10 per group) were dosed for 20 days (study days 1-20) by gavage to 0, 50, 150 or 250 mg/kg/d InCl3. Males (10 per group) were dosed for 17 days (study days 3-20) by gavage to 0, 50, 150 or 250 mg/kg/d. Males and females were cohabited and mated on study days 7-11. Systemic toxicity results showed a functional renal effect and a reduction in circulating lymphocyte number in adult males (high dose) and a significant reduction in adult male and female bodyweight (all doses). These effects occurred in the absence of effects on microscopic structure of selected male tissues (including right testis and epididymis), male reproductive parameters (sperm motility assessment and fertility before and during chemical administration) or female fertility endpoints (percentage pregnant, number of live and dead implants, number of corpora lutea and number of uterine implant sites at necropsy). The study demonstrated no effect of indium chloride on male or female fertility and reproductive performance (ability to deliver any young).

Link to relevant study records

Reference

Endpoint:

reproductive toxicity, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

Short-term reproductive toxicity screen. Female Swiss mice (group 1) were dosed for 20 days (study days 1-20) by gavage to 0, 50, 150 or 250 mg/kg/d InCl3. Males (group 3) were dosed for 17 days (study days 3-20) by gavage to 0, 50, 150 or 250 mg/kg/d. Males and females were cohabited and mated on study days 7-11.

GLP compliance:

no

Limit test:

no

Species:

mouse

Strain:

Swiss

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Labs (Raleigh, NC)
- Age at study initiation: (P) 55-65 days
- Weight at study initiation: (P) 27-31g
- Housing: polycarbonate shoebox cages with harwood bedding (BetaChips, Northeastern Products Corp, Warrensburg, NY)
- Diet (ad libitum): NIH-07 feed
- Water (ad libitum): deionized water
- Acclimation period: 10-14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1°C
- Humidity (%): 50 ± 10%

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

The test substance was dissolved in water at concentrations between 5 and 35mg/ml and administred to adult male and female Swiss mice daily by oral gavage.

Details on mating procedure:

- M/F ratio per cage: 1:1 or 1:2
- Length of cohabitation: Males and females were cohabited and mated on study days 7-11
- Proof of pregnancy: Sperm in vaginal smear or plug during cohabitation

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No data

Duration of treatment / exposure:

-males (group 3): dosed from study day 3 until study day 20
-females (group 1): continuously exposed: day 0 until day 20
-females (group 2): gestational exposure: day 8 until day 14

Frequency of treatment:

Daily

Details on study schedule:

Males (group 3) are, prior to chemical exposure, cohabited with a group of females (group2) for the first 3 days of the study. The animals are separated at the end of cohabitation. The females are housed until they are dosed from gestation day 6-15. They are allowed to give birth, and rear their young until postnatal day 4. Meanwhile, the males are dosed from study day 3 until 20. These males are again mated with another group of females (group1) from study day 7 until 11. During this time, both sexes are treated with the compound.

Dose / conc.:

50 mg/kg bw/day

Dose / conc.:

150 mg/kg bw/day

Dose / conc.:

250 mg/kg bw/day

No. of animals per sex per dose:

10

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale:
A 22-day dose-range-finding (DRF) study was conducted to set doses for the main study. This DRF study involved no mating, just dosing to group-housed adult rats. Doses tested were: 50, 150, 250 and 350 mg/kg/d.

Positive control:

None

Parental animals: Observations and examinations:

BODY WEIGHT: Yes
- Time schedule for examinations: group 1 females: day 0,4,12,16,20,21; group 3 males: day 3,7,11,15,19,21; group 2 females: gestation day 0, 8, 12, 15 and post natal day 1, 4

Oestrous cyclicity (parental animals):

Number of live/dead implants
Total implants/corpora lutea

Sperm parameters (parental animals):

Parameters examined in male parents:
Epididymal sperm motility and total epididymal sperm count

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
Number of pups, stillbirths, live births, postnatal mortality, weight gain

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals at day 21
- Maternal animals: All surviving animals after postnatal day 4
HISTOPATHOLOGY / ORGAN WEIGHTS: on liver, kidney, testis

Postmortem examinations (offspring):

No data

Statistics:

Initial and terminal body weights, body weight changes, absolute and relative organ weights, and conceptus and pup data were analyzed to detect dose-related trends using Jonckheere's test against ordered alternatives followed by the Mann-Whithney U test for pairwise comparisons. An exact permutation test was used to detect dose-related trends in fertility rates and neonatal deaths.

Reproductive indices:

None

Offspring viability indices:

None

Clinical signs:

not specified

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

not specified

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS):
group 1 (males): dose related decrease in body weight gain, with the high dose animals losing weight during the study. Food consumption is reduced during the first 11 days of exposure only in the high dose group
group 2 (females- continuously exposed): animals in the top dose group consumed slightly less food than controls and gained less than half the weight that controls gained during the course of the study
group 3 (females -gestational exposure): females dosed during fetal organogenesis with the high dose level consumed less food than controls, and animals in the middle dose group consumed less food from gestational day 8-12. There was a dose-related inhibition of weight gain that started at the lowest dose group, and animals in both middle and high dose groups gained significantly less weight during the experiment and finished lighter than controls.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS): no change in any fertility endpoint (number of live implants, number of dead implants, number of resorptions, number of corpora lutea

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS): no effects on sperm parameters, fertility before and during chemical administration (group 1 males)

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS): no adverse effects seen

ORGAN WEIGHTS (PARENTAL ANIMALS): no effects on organ weights (group 1 males)

HISTOPATHOLOGY (PARENTAL ANIMALS): No changes in the structure of kidneys or livers (known target organs of cadmium toxicity) (sytemic toxicity only evaluated in males)

OTHER FINDINGS (PARENTAL ANIMALS): eosinophils were reduced at the high dose group. Serum enzymes indicative of liver damage were slightly increased in the high dose group. Serum albumin levels were increased slightly; no increase in Cd-U or in protein levels

Dose descriptor:

NOAEL

Remarks:

reproductive

Effect level:

250 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive function (oestrous cycle)

reproductive function (sperm measures)

reproductive performance

Clinical signs:

not specified

Mortality / viability:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings:

not specified

VIABILITY (OFFSPRING): there was an increase in fetal death (dead pups at birth) at the highes dose (250mg/kg/d)
BODY WEIGHT (OFFSPRING): live-born high-dose pups weighted less than controls at birth and on PND1

Dose descriptor:

NOAEL

Generation:

F1

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: overal effects: viability: there was an increase in fetal death (dead pups at birth) at the highest dose (250mg/kg/d) body weight: live-born high-dose pups weighted less than controls at birth and on PND1

Remarks on result:

not measured/tested

Reproductive effects observed:

no

none

Conclusions:

No evidence of reproductive performance toxicity in the presence of adult systemic toxicity. InCl3 dosed orally up to 250mg/kg/d had no effect on the reproductive performance of either male or female animals.
Overall the available data indicate that InCl3 is not classifiable as a reproductive toxicant

Executive summary:

A sub chronic toxicity and male / female fertility study conducted in Swiss mice designed to assess the effects of indium chloride on male and female gametogenesis, female cyclicity, fertilization and implantation. Female Swiss mice (10 per group) were dosed for 20 days (study days 1-20) by gavage to 0, 50, 150 or 250 mg/kg/d InCl3. Males (10 per group) were dosed for 17 days (study days 3-20) by gavage to 0, 50, 150 or 250 mg/kg/d. Males and females were cohabited and mated on study days 7-11. Systemic toxicity results showed a functional renal effect and a reduction in circulating lymphocyte number in adult males (high dose) and a significant reduction in adult male and female bodyweight (all doses). These effects occurred in the absence of effects on microscopic structure of selected male tissues (including right testis and epididymis), male reproductive parameters (sperm motility assessment and fertility before and during chemical administration) or female fertility endpoints (percentage pregnant, number of live and dead implants, number of corpora lutea and number of uterine implant sites at necropsy). The study demonstrated no effect of indium chloride on male of female fertility and reproductive performance (ability to deliver any young). 

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

250 mg/kg bw/day

Study duration:

subchronic

Species:

mouse

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

There is little information available regarding the effect of indium upon reproductive performance. In the one available study (combined reproductive and developmental toxicity in Swiss mice) InCl3 dosed orally up to 250mg/kg/d had no effect on the reproductive performance of either male or female animals (Chapin et al, 1995).

Effects on developmental toxicity

Description of key information

In the OECD Guideline 414-Prenatal developmental toxicity study (Ungvary et al. 2000), the maternal and developmental toxicity NOAEL for rats and rabbits was 50 mg/kg bw. The LOAEL (maternal and developmental toxicity) in rats was 100 mg/kg and in rabbits (maternal and developmental) was 200 mg/kg (except for the possibility of renal effects in the foetuses at the 100mg/kg level). Increasing dose above the NOAEL, increased post-implantation loss, reduced fetal body weight and increased skeletal and visceral retardation. The main target organ in the rat and rabbit dams was the kidney.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: LATI, Gödöllö
- Weight at study initiation: 210-240g
- Housing: climatized animal house, plastic cages, on steam-sterilized, hardwood shavings
- Diet (ad libitum): standard rat pellets (LATI, Gödöllö)
- Water (ad libitum): tap water

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 40-70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): hours 06-08, dim light; 08-18, daylight; 18-20, dim light; 20-06, darkness

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

none

Details on mating procedure:

Rats were mated as follows: Males were placed among the females overnight. Vaginal smears were taken daily and stained with 1% methylene
blue solution. The day when sperm were found in the vaginal smear of the females in estrus was regarded as the first day of gestation.

Duration of treatment / exposure:

-rats treated with 0, 50, 100, 200 and 400 mg/kg bw on GD 6-15
-rats treated with 0, 400 mg/kg bw on one of GD 8, 9, 10, 11, 12, 13, 14 or 15

Frequency of treatment:

daily

Duration of test:

21 days

Dose / conc.:

50 mg/kg bw/day

Dose / conc.:

100 mg/kg bw/day

Dose / conc.:

200 mg/kg bw/day

Dose / conc.:

400 mg/kg bw/day

No. of animals per sex per dose:

No. of pregnant animals/group:
control: 33
Gestation days6-15 :
50 mg/kg: 20
100 mg/kg: 20
200 mg/kg: 20
400 mg/kg: 21

Control animals:

yes, concurrent no treatment

Details on study design:

none

Maternal examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes

FOOD CONSUMPTION: Yes

WATER CONSUMPTION : Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #21
- Organs examined: brain, hypophysis, thymus, lungs, heart, liver, spleen, kidneys, adrenals, and ovaries , stomach, and uterus

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes:
- Soft tissue examinations: Yes:
- Skeletal examinations: Yes
- Head examinations: No

Statistics:

Parametric data (maternal organ weights, clinical and biochemical parameters, food and fluid consumption, fetal and placental weights) of groups were compared using analysis of variance and Dunnett’s test, while nonparametric variables (maternal weight gain, frequencies of pre- and postimplantational lossess, frequencies of body weight, skeletal and internal organ retardations, minor and major anomalies) of groups were compared using a Kruskal–Wallis test. The level of significance was chosen at 5%.

Indices:

none

Historical control data:

none

Mortality:

no mortality observed

Description (incidence):

no death occurred

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

dose-related inhibition of weight gain

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

significant decrease with increasing doses of InCl3; the greatest reduction in the group treated with 400 mg/kg

Food efficiency:

not specified

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

following parameters did not change markedly: red and white cell counts, hematocrit, MCV, MCH, and MCHC values, hemoglobin, serum total protein, albumin concentrations

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

bilirubin concentration, and AST and ALT acitiviets in serum significantly decreased

Urinalysis findings:

not examined

Behaviour (functional findings):

not specified

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

at the highest dosage (400mg/kg), the relative weights of liver, pancreas, and brain increased

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

hemorrhagic foci at the cortico-medullar border in the interstitium of the kidneys of dams treated with 400 mg/kg indium chloride

Histopathological findings: neoplastic:

no effects observed

Number of abortions:

no effects observed

Pre- and post-implantation loss:

effects observed, treatment-related

Dead fetuses:

effects observed, treatment-related

Details on maternal toxic effects:

Details on maternal toxic effects:
- Mortality and time to death: no death occurred
- Body weight gain: dose-related inhibition of weight gain
- Food consumption: significant decrease with increasing doses of InCl3; the greatest reduction in the group treated with 400 mg/kg
- organ weights: at the highest dosage (400mg/kg), the relative weights of liver, pancreas, and brain increased
- clinical parameters: bilirubin concentration, and AST and ALT acitiviets in serum significantly decreased

Key result

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Key result

Dose descriptor:

LOAEL

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Fetal body weight changes:

effects observed, treatment-related

Reduction in number of live offspring:

effects observed, treatment-related

External malformations:

effects observed, treatment-related

Skeletal malformations:

effects observed, treatment-related

Visceral malformations:

effects observed, treatment-related

Details on embryotoxic / teratogenic effects:

Details on embryotoxic / teratogenic effects:
-postimplantation loss, frequency of fetuses with retarded body weight, skeletal and visceral retardation: significantly increase with dose of InCl3
-gross external malformations, visceral anomalies, congenital major skeletal anomalies: significantly increase with dose of InCl3

Key result

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: % of malformed fetuses

Key result

Dose descriptor:

LOAEL

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: % of malformed fetuses

Abnormalities:

effects observed, treatment-related

Localisation:

external: tail

skeletal: forelimb

skeletal: sternum

skeletal: rib

skeletal: vertebra

skeletal: hindlimb

visceral/soft tissue: urinary

visceral/soft tissue: male reproductive system

Developmental effects observed:

yes

Lowest effective dose / conc.:

100 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects as a secondary non-specific consequence of maternal toxicity effects

Dose response relationship:

yes

Relevant for humans:

no

Indium concentration in the maternal blood was increased dose-dependently 24 h after oral administration. Indium appeared also in the fetal blood in concentrations lower than that found in maternal blood. For the lowest and highest doses, indium concentrations in the fetal blood were 33% and 11% of those in maternal blood, respectively.

Conclusions:

InCl3 was teratogenic and embryotoxic but only at maternally toxic doses

Executive summary:

Daily indium chloride doses of control ( 0) , 50, 100, 200, or 400 mg/ kg were administered orally to Sprague-Dawley rats by gavage, on d 6–15 of gestation, and daily metal doses of control ( 0) , 50, 100, or 200 mg/ kg were administered to New Zealand rabbits on d 6–20 of gestation. Further groups of pregnant rats were treated with control ( 0) or 400 mg/ kg indium chloride orally on one of d 8, 9, 10, 11, 12, 13, 14, or 15 of gestation. The dams and fetuses were examined on d 21 ( rats) and 30 ( rabbits) of gestation, using standard teratological methods. Indium concentrations in maternal and fetal blood of rats increased dose-dependently. Percentage bioavailability of indium in the dams increased with increasing dose. Indium concentration in fetal blood was lower than that of the dams being 33 and 11% of that of the dams at the lowest and highest doses, respectively.
The repeat oral administration of indium chloride to pregnant SD rats from GD 6 through 15 (positive for sperm presence = GD 1) induced rudimentary tail, anury, syndactyly, clubfoot, exencephaly, undescended testis, dilatation of the renal pelvis and ureter, and skeletal anomalies of the rib, vertebrae, and sternebrae in GD 21 fetuses at 100 mg/kg/day. The repeat oral administration of indium chloride to pregnant New Zealand rabbits from GD 6 through 20 (positive for sperm presence = GD 1) induced renal agenesia and ectopic kidney in GD 30 fetuses at 100 mg/kg/day or more. The maternal and fetal toxicity NOAEL for rats and rabbits was 50 mg/kg bw. The LOAEL (maternal and fetal toxicity) in rats was 100 mg/kg and in rabbits (maternal and fetal) was 200 mg/kg (except for the possibility of renal effects in the foetuses at the 100mg/kg level). Increasing dose above the NOAEL, increased post-implantation loss, reduced fetal body weight and increased skeletal and visceral retardation. Fetal retardation in rats was independent of exposure time (not tested in rabbits) occurring after oral administration of 400 mg/kg InCl3 on days 10, 11, 12, 14 or 15 of gestation. A single oral dose of 400 mg/kg InCl3 resulted in a maternal blood indium concentration of 1038 ug/l. Unlike continuous administration of InCl3 on GD 6-15, there were no major anomalies of the fetal urogenital system in rats following single day administrations. In rabbits there was a low overall malformation rate of 3.5 and 6.3% at 100 and 200mg/kg bw but this was considered positive when compared to the usual spontaneous malformation rate in rabbits of 0.7 – 4.2% and the malformations were renal which has a usual malformation rate of <1%. Decreased weight gain was seen in both rat and rabbit dams but decreased weight gain alone was not associated with teratogenic or embryolethal effects which were seen only when bilirubin concentration and AST and ALT activities were significantly decreased in dams (rats – no information on rabbits). The main target organ in the rat and rabbit dams was the kidney.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

50 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

With the exception of the key study Ungvary et al., 2000, all of the supporting studies reviewed, have significant limitations in design and reporting. These limitations include inadequate animal numbers, non-relevant routes of exposure, limited bioavailability assessment and significant differences in the levels of indium measured in maternal and fetal blood following similar oral doses.

Ungvary et al, 2000 shows InCl3 was teratogenic and embryotoxic but only at maternally toxic doses. The study demonstrates also that developmental effects are not independent of effects on the livers of the dams. Effects on the liver mixed function monooxygenase systems (MFO's) of the dams are likely as indirectly indicated by AST, ALT and bilirubin changes. Such changes may affect sex steroid metabolism which, in turn, may contribute to embryotoxicity and teratogenicity. No data on the levels of sex steroids in the blood of treated animals was available.

Toxicity to reproduction: other studies

Description of key information

No data identified

Mode of Action Analysis / Human Relevance Framework

No data identified

Justification for classification or non-classification

There is no experimental evidence that would justify a classification of indium chloride (InCl3) for hazardous effects for reproductive or developmental toxicity under the Regulation (EC) 1272 -2008 on the classification, labelling and packaging of substances and mixtures.

Overall, the available data are not supportive of a category 1A or 1B reproductive toxicant classification as there is no conclusive evidence that the effect of indium on the conceptus is independent of maternal toxicity in experimental animals and it cannot be assumed that the effect in the fetus is not a consequence of the effect on the dams. Classification as a Class 2 reproductive toxicant is also questionable based on the available data. Developmental effects in vivo in the absence of maternal toxicity have only been demonstrated following iv exposure of the dams to indium which is not a relevant route of exposure. Also, the blood concentrations required in vivo in the dams to cause developmental toxicity following iv exposure are significantly in excess of those concentrations achievable via oral exposure. The guidance for category 2 classification also indicates that any reproductive effects should be in the absence of other toxic effects, or if occurring with other toxic effects the adverse effect on reproduction is considered not to be a secondary non-specific consequence of the other toxic effects. The available data does not allow for this conclusion to be drawn and therefore does not support a category 2 classification.

The available reproductive and developmental toxicity information has been exclusively generated with soluble indium compounds (indium trichloride) which ensure maximum bioavailable concentration of indium and hence, allow the use of the information also for the assessment of the slightly soluble/insoluble indium compounds or metal on a read across basis.