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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline Study
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2007

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Principles of method if other than guideline:
According to OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Nickel sulfate hexahydrate
- 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
- Physical state: blue-grean appearance
- Impurities: Co 8 ppm, Na 3 ppm, Fe 2 ppm, Mg 0.7 ppm, Ag 0.2 ppm
- Purity: 99.99+%
- Lot No.: 02221PQ
- Source: Sigma Aldrich
- Other details not reported or not applicable

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, NC, USA.
- Age at study initiation: 8 weeks
- Weight at study initiation: 239-267 g
- Assigned to test groups randomly: [no/yes, under following basis: ]
- Fasting period before study: not reported
- Housing: 2 per cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 64 - 79 deg F
- Humidity (%): humidity 30-70%
- Air changes (per hr): 10 per hr
- Photoperiod (hrs dark / hrs light): 12 hr light/dark cycle.

IN-LIFE DATES: From: April 21, 2003 To: Aug. 2003

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: Cell culture control water
- Lot No: 017156 and 01100526
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: each day the test article was prepared by adding to the vehicle. Formulations held at room temperature.
Animals were dosed by oral gavage once daily for three consecutive days to six males per dose level. The dose levels were 125, 250, or 500 mg/kg/day.

DIET PREPARATION
- not applicable
Duration of treatment / exposure:
3 days
Frequency of treatment:
Once daily
Post exposure period:
24 hours after 3rd dose
Doses / concentrations
Remarks:
Doses / Concentrations:
125, 250, 500 mg/kg-d
Basis:
nominal conc.
No. of animals per sex per dose:
6 per dose
Control animals:
yes, concurrent vehicle
Positive control(s):
Cyclophosphamide was used as the positive control administered by oral gavage dissolved in deionized water at a dose of 60 mg/kg

Examinations

Tissues and cell types examined:
Animals were euthanized approximately 24 hours after the third dose for extraction of bone marrow.
Blood was also collected prior to euthanization.
Nickel in bone marrow and blood was analyzed by AAS.
Details of tissue and slide preparation:
Following centrifugation to pellet the marrow, the supernatant was spread on slided fixed with methanol and stained in acridine orange, dried, and analyzed under fluorescent microscopy.
Evaluation criteria:
Slides were scored for micronuclei and to determine the PCE to NCE cell ratio. The percent micronucleated cells was determine by analyzing micronuclei from at least 2000 PCEs per animal. The criteria were those of Schmid 1976.
Statistics:
Data analysis was conducted using ANOVA

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: 125-1750 mg/kg-day
- No cytotoxicity observed at 750 or 1000 mg/kg-day. Mean PCE:NCE ratios were 0.32 and 0.64 compared to 0.81 (control)
- Other: the maximum tolerated dose was estimated at 500 mg/kg-day

RESULTS OF DEFINITIVE STUDY
Clinical signs of toxicity were noted in all treatment animals including hypoactivity, salivation, black feces, irregular respiration, squinted/closed eyes.

No mortality occurred.

Nickel did not significantly increase micronucleated PCEs at any dose level. Nickel was not significantly cytotoxic to bone marrow at any dose level.
Dose-dependent nickel concentrations were detected in plasma and bone marrow samples.

The author's suggest the results support the non-genotoxic mode of action for soluble nickel.

Applicant's summary and conclusion

Conclusions:
The test article, nickel sulfate hexahydrate, was evaluated as negative in the rat bone marrow micronucleaus assay under the conditions of this assay.
Executive summary:

STUDY RATED BY AN INDEPENDENT REVIEWER.