Nickel di(acetate)

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1985-1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards with acceptable restrictions Test animals experienced decreased water comsumption due to taste aversion; Animal room climate controls failed at one point during study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

Parental exposure exceeds the OECD Guideline as this was the F2b generation from a 2-Generation study

Principles of method if other than guideline:

The study design exceeded the guideline through the inclusion of F1b and F2b generations for ancillary assessments. These assessments included a complete developmental toxicity assessment in the F2b generation.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Nickel dichloride

EC Number:

231-743-0

EC Name:

Nickel dichloride

Cas Number:

7791-20-0

Molecular formula:

Cl2Ni

IUPAC Name:

Nickel (II) chloride hexahydrate

Specific details on test material used for the study:

- Name of test material (as cited in study report): Nickel Chloride Hexahydrate (7791-20-0)
- Molecular formula (if other than submission substance): not different than submission substance
- Molecular weight (if other than submission substance): not different than submission substance
- Smiles notation (if other than submission substance): not different than submission substance
- InChl (if other than submission substance): not different than submission substance
- Structural formula attached as image file (if other than submission substance): not different than submission substance
- Substance type: pure product
- Physical state: green, deliquescent crystals or crystalline powder
- Solubility: water (20°C) 254 g/100 ml
- Other details on test material are included in the study report

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

Animals and Husbandry
The experimental animals in the present study were viral antibody free (VAF/Plus) @ Crl:CD (SD)BR outbred albino rats supplied by Charles River Breeding Laboratories. Inc. (Kingston, NY). The Charles River CD rat was selected as the experimental animal assigned to this investigation. Males and females were 27-32 days old at the time of arrival at RTI.

During the quarantine period (10-14 days), animals were randomly assigned to cages. and individually coded tags were affixed to one ear of each rat. All animals were singly housed throughout the study in solid bottom polycarbonate or polypropylene cages (8" x 19" x 10 1/2") with stainless steel wire lids and molded filter tops. Ab-Sorb-Dri cage litter was used in all cages.

Purina Certified Rodent Chow (No. 5002, pelletized) was available ad libitum throughout the study. Rodent chow was stored at 55-60°F and the period of use did not exceed five months after receipt at RTI. Deionized/filtered water was available ad libitum during the quarantine period. During the exposure period animals were given ad libitum access to either control water (i.e., deioniied/filtered water with pH=4.0-6.0 adjusted with hydrochloric acid) or to an aqueous solution of nickel chloride. Clear plastic water bottles with stainless steel sipper tubes were used throughout this investigation. The animal holding room assigned for this study was equipped with individual temperature and humidity controls.

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Details on exposure:

RTI (1988) administered nickel chloride hexahydrate to male and female CD rats (30/sex/dose) at (0, 7.3, 30.8 and 51.6 mg Ni/kg bw/day, estimated overall) in a 2-generation study. An additional dose level of 1000 ppm was eliminated after 2 weeks due to excessive toxicity. The parental animals were exposed beginning 11 weeks before cohabitation, and exposure continued for a total of 24 weeks (males) or 30 weeks (females). Groups of 10 rats/sex comprised a satellite subchronic non breeder study. The average nickel consumption reported by the authors varied by more than a factor of 2, with the highest consumption at the beginning of the premating exposure and during the latter part of the lactation period. As a conservative estimate, the average exposure during gestation, which was on the low end of overall exposure levels, was used as the dose level for each group. This choice also takes into account the possibility that gestational exposure alone could have accounted for observed the effects. Thus, the estimated doses were 0, 6.0, 25, and 42 mg Ni/kg bw/day.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Analytical purity: 99% as reported by vendor; >98% as reported by ICP analysis at RTI
- Stability: stability of aqueous solutions for 15 days under the anticipated conditions of use was verified by RTI for concentrations of 100 ppm Ni++ and greater
- Vehicle: Filtered/deionized water. Durham, NC city tap water was pre-filtered with 0.5 micron Nucleopore membrane filters to remove fine particulate matter. Organics were removed by charcoal adsorption. Then water was deionized by passage through two mixed-bed ion exchangers. The filtration and deionizing systems were purchased from and are routinely serviced by Hydro Ultrapure Water Systems, Inc., P. O. Box 2855, Durham, NC 27705

Details on mating procedure:

1 male and 1 female cohabited for up to 2-weeks; mating confirmed by positive spermatozoa on vaginal lavage

Duration of treatment / exposure:

Parental animals were exposed beginning 11 weeks before cohabitation and exposure continued for a total of 24 weeks (males) or 30 weeks (females

Frequency of treatment:

Daily

Duration of test:

F1b males and females of the RTI (1988) study were randomly mated on postnatal day 70 and their offspring (F2a and F2b) were evaluated through postnatal day 21. This phase included teratological evaluations of F2b fetuses.

No. of animals per sex per dose:

30/sex/dose

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

Live body weight (g). was recorded for individual Fl males and females at least weekly between pnd 21 and pnd 42. Beginning on study week 32, body weight for F1 males and females was recorded once per week for the remainder of the study except during cohabitation or during gestation and lactation when female body weight was recorded on postcohabitation days (pcd) 0, 6, 13, and 20 (if a litter had not been delivered by pcd 24 body weight was also recorded on that day), as well as on postnatal days (pnd) 1, 4, 7, 14, and 21 (dams were weighed on the designated postnatal days only if a litter was present on the day of measurement). Food consumption (g) and water consumption (g) were recorded at each occasion when body weights were recorded (except on pnd 4. per the study protocol) or when food or water was added to the cages. Average daily consumption of food and water (g/animal/day and g/kg/day) was calculated for each dose group. During cohabitation, collective food and water consumption was recorded for each breeding pair. During lactation, food and water consumption were expressed as the total intake per dam recognizing that intake by the offspring contributed to this measure during the later stages of lactation.

Throughout the study, each male and female was observed daily for clinical signs of toxicity. morbidity. or mortality. beginning on day 0. and continuing until scheduled sacrifice. Clinical signs observed during handling of the animal were recorded at the time of weighing; on all other days recorded observations were based upon cage-side observations. For any F1 animal found dead or sacrificed in extremis. the date and time of the observation was recorded, the animal was weighed and necropsied as soon as possible for external and internal signs of toxicity, and a final measurement of food and water intake was taken.

Ovaries and uterine content:

During evaluation of Fl dams and F2a litters. the following measures were recorded: length of gestation, number of pups per litter, number of live pups per litter, number of dead pups per litter, percentage of male pups per litter, individual pup body weight (pnd 1, 4, 7, 14, and 21), external (gross) anatomical malformations. and any other clinically abnormal condition observable at cage-side or at weighing. On pnd 4. litters were culled to a maximum size of 10 giving consideration to equal representation of males and females when possible.

Fetuses from the F2b litters were collected at sacrifice of the dam on gd 20. The parameters measured were number of corpora lutea per dam, Implantation sites per litter, resorptions per litter, dead fetuses per litter, nonlive implants per litter (dead fetuses plus resorptions), adversely affected implants per litter (nonlive implants or malformed live fetuses), live fetuses per litter, sex of fetus and individual fetal body weight.

Fetal examinations:

At normal weaning age (pnd 21) all F2a pups were sacrificed and a gross necropsy performed.

Fetuses from the F2b litters were collected at sacrifice of the dam on gd 20. Fetuses were examined for external. visceral. and skeletal abnormalities. as well as other anatomical variations.

Statistics:

When experiment-wise tests revealed a significant difference among the doses then a test of pair-wise differences between the control and each dosed group was performed. For parameters that were expected to conform to the parametric assumptions of normality and homogeneity of variance, the following tests were used to examine the experiment-wise effect of dose, dose response trend, and pair-wise effect of dose, respectively: one-way analysis of variance (Snedecor and Cochran, 1967), simple linear regression (Snedecor and Cochran, 1967), Williams' Test (Williams, 1971 and 1972) and Dunnett's Tests (Dunnett, 1955 and 1964). When the data were expected to violate the assumptions of the parametric tests, then similar nonparametric tests were used. When data were continuous or approximately continuous but not normally distributed, the KruskalWallis (Siegel, 1956), Mann-Whitney U (Siegel, 1956), and Jonckheere's (Jonckheere, 1954) tests were used to examine the experiMent-wise effect of dose, the pair-wise effect of dose, and the dose response trend, respectively. For nonparametric pair-wise cOMparisons of individual groups against the controls, the following tests were used: (I) for data with a significant Kruskal-Wallis Test (p<0.05) and evidence of a trend (p<0.10, Jonckheere's Test), Shirley's multiple comparison procedure (Shirley, 1977) was used to determine the smallest dose at which there was a statistically significant effect, or (2) for data with a significant Kruskal-Wallis Test (p<0.05) and no evidence of a trend (p>O.IO, Jonckheere's Test), Dunn's Test, a nonparametric analogue to Dunnett's Test was applied (Dunn, 1964). Index (categorical) data were analyzed using the Chi-Square Test for Independence (Snedecor and Cochran, 1967), Fisher's Exact Probability Test (Snedecor and Cochran, 1967), and the Test for Linear Trend on Proportions (Snedecor and Cochran, 1967) for the detection of the experiment-wise, pair-wise, and trend effects of dose, respectively.

Historical control data:

Available

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Evaluation of the data indicated that the 500 ppm dose caused significant body weight depression of both mothers and pups, and increased neonatal mortality during the postnatal development period. The intermediate dose, 250 ppm nickel, produced transient depression of maternal weight gain and water intake during gestation of the F2b litters.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

ca. 6 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

LOAEL

Effect level:

ca. 42 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Details on embryotoxic / teratogenic effects:
The 50 ppm nickel exposure caused a significant increase in short ribs (11%). However, since this effect was not seen in both the higher dose groups, the reported incidence of short ribs in the 50 ppm group is not considered to be biologically significant.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

ca. 42 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified