Phosphine

Genetic toxicity: in vivo

Administrative data

Endpoint:

genetic toxicity in vivo

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Protocols for the care, treatment and killing of the mice were approved by the Animal Care Committees of the Health Effects Research Laboratory of the US EPA and the NIEHS and meet all guidelines set by the National Institutes of Health.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Cytogenetic and germ cell effects of phosphine inhalation by rodents: II. Subacute exposures to rats and mice.

Author:

Kligerman A.D., Bishop J.B., Erexson G.L., Price H.C., O'Connor R.W. and Morgan D.L.

Year:

1994

Bibliographic source:

Environ Mol Mutagen 24(4):301-306

Materials and methods

Principles of method if other than guideline:

Rodents are exposed to target concentrations of phosphine by inhalation for an appropriate period and are sacrificed at appropriate times after treatment. Specific cells are collected (blood leukocytes) and treated to study specific endpoints (sister chromatide exchange) chromosome aberrations

GLP compliance:

not specified

Type of assay:

sister chromatid exchange assay

Test material

Test material information

Constituent 1

Reference substance name:

Phosphine

EC Number:

232-260-8

EC Name:

Phosphine

Cas Number:

7803-51-2

Molecular formula:

H3P

IUPAC Name:

phosphane

Details on test material:

gas was procured in cylinders containing 2,500 ppm PH3 in nitrogen (AGA specialty Gas, Inc, Maumee, OH).

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Details on test animals or test system and environmental conditions:

After exposition, male mice (approximately 8 weeks of age) were returned to the holding cages with food and tap water ad libitum. Animals were maintained on a 12 hours light/dark cycle with controlled temperature and humidity.

Administration / exposure

Route of administration:

inhalation: gas

Vehicle:

The desired exposure concentration were obtained by introducing metered quantities of PH3 directly into the process air stream just prior to a set of static mixing element.

Details on exposure:

Male mice were placed in the inhalation chambers without food or water and exposed to target concentration.

Duration of treatment / exposure:

9 days over 11 day period (5 days exposed, 2 days off, 4 days exposed)

Frequency of treatment:

6 hours per day.

Post exposure period:

18 to 20 hours.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1.25 ppm
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
2.5 ppm
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
5 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

5 animals per dose

Control animals:

yes

Positive control(s):

No data

Examinations

Tissues and cell types examined:

Peripheral blood smears.

Details of tissue and slide preparation:

Blood was removed by cardiac puncture.
For the mouse blood, isolated mononuclear leukocytes were collected by density gradient centrifugation and cultured for the analyses of sister chromatid exchange and chromosome aberrations in Peripheral blood lymphocyte and micronucleus in cytochalasin B-induced binucleated lymphocyte.
3 µg/ml phytohemagglutinin was used to stimulate mitogenisis in each 1 ml culture containing RPMI-1640 20% heat-inactivated fetal bovine serum, 1% L-gllutamine, 1% penincillinstreptomycin and between 2 and 5*10E5 mononuclear leukocytes. After 21 hours, 5 µM 5-bromo-2'-deoxyuridine was added for analyses of sister chromatid exchanges, chromosome aberration and cell cyle progession. In cultures used for Micronnuclei analysis in binucleated, instead of BrdUrd, 3 µg/L cytochalasin B wad added at 21 hours to prevent cytokinesis. All cultures for sister chromatid exchanges and chromosome aberrations analyses were harvested by centrifigation at 44 hours postinitiation following a 3 hours 0.5 µg/L demecolcine treatment. Cultures for micronucleis analysis in binucleated by centrifugation at 51 hours.
For mouse cultures used for analyses of analyses of sisterchromatid and chromosome aberration, cells were treated with a hypotonic 0.075M KCl solution and fixed in 3:1 methanol:acetic acid. Slides were made, mounted and stained.

Evaluation criteria:

For each animal, 50 division metaphases were analysed for sisterchromatid exchange. The replicative index was calculated from 100 consecutive metaphases.

Statistics:

For Sisterchromatid exchange and cell cycle studies, a one way analysis of variance was calculated and if significant, a Least Significant difference test was used to compare treatment to control.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Remarks:

Peripheral Blood lymphocyte

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

PH3 inhalation caused no statistically significant increases in Sister Chromatid exchange in peripheral blood lymphocyte..
In addition, all of the chromosome aberrations observed were either simple chromatid or chromosome deletions and no highly damaged cells or complex exchanges were seen.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative Peripheral Blood lymphocyte
No increase in cytogenetic end points (sisterchromatide exchange) was observed over controls in cultured lymphocytes.
The concentrations of PH3 up to 5 ppm (7.1 mg/m3) are not genotoxic to rodents when administrated by inhalation for 9 days during an 11 day period.

Executive summary:

Male B6C3F1 mice were exposed to 0 ; 1.25 ; 2.5 or 5 ppm of phosphine to 6 hours per day for 9 days over an 11 days period. Approximately 20 hours after the termination of exposure, blood was removed from the mice and the lymphocytes cultured for analyses sister chromatid exchanges No significant increase in sisterchromatide exchange was observed over controls in cultured lymphocytess.