Magnesium methanolate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian cell study: DNA damage and/or repair

Remarks:

Type of genotoxicity: DNA damage and/or repair

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: scientifically acceptable publication

Data source

Reference

Reference Type:

publication

Title:

Methanol Exposure Does Not Lead to Accumulation of Oxidative DNA Damage in Bone Marrow and Spleen of Mice, Rabbits or Primates.

Author:

McCallum, G.P., Siu, M., Ondovcik, S.L., Sweeting, J.N., Wells, P.G.

Year:

2010

Bibliographic source:

Molecular Carcinogenesis 9999: 1 - 10

Materials and methods

Principles of method if other than guideline:

This study was performed to determine whether MeOH could indirectly DNA damage via ROS-mediated mechanism. Animals (mice, rabbits and monkeys) were treated with either once or for 15 days with 2.0 g/kg MeOH i.p.. Oxidative DNA damage was observed by measuring 8-oxo-2'-deoxyguanosine. Lipid peroxidation in bone marrow and spleen homogenates was determined by measuring the Ievels of HNE-His protein adducts.

GLP compliance:

not specified

Type of assay:

other: oxidative DNA damage

Test material

Test material information

Constituent 1

Reference substance name:

Methanol

EC Number:

200-659-6

EC Name:

Methanol

Cas Number:

67-56-1

Molecular formula:

CH4O

IUPAC Name:

methanol

Details on test material:

- Name of test material (as cited in study report): MeOH
- Physical state: liquid
- Analytical purity: HPLC grade

Test animals

Species:

other: mouse, rabbit, monkey

Strain:

other: CD-1, New Zealand white, cynomolgus

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: mice, rabbits and monkeys: Charles River Laboratories
- Age at study initiation: mice: 9 - 13 weeks; rabbits: 5 months; monkeys: 3.4 - 5.7 years
- Weight at study initiation: rabbits: 3.25 - 3.75 kg, monkeys: 2.8 - 4.8 kg
- Diet: mice: rodent chow ad libitum; rabbit: standard high-fiber rabbit chow; monkeys: certified primate chow diet (# 5048) from Purina Mills (St. Louis, MO) supplemented with fruit or vegetables 2-3 times weekly
- Water: mice, rabbit and monkeys: ad libitum
- Acclimation period: monkeys: two weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): mice and rabbits: 20°C; monkeys: 18 - 29°C
- Humidity (%): mice: 50%, rabbits: 60%
- Photoperiod (hrs dark / hrs light): mice: 10/14; rabbits and monkeys: 12/12

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: saline

Details on exposure:

Mice: Drugs were administered via intraperitoneal (ip) injection using a 26 gauge (G) 3/8 needle.
Rabbits: by ip injection usinga 23 G needle
monkeys: were lightly sedated with ketamine (ca. 5 - 10 mg/kg) for dose administration and then administered MeOH (2g/kg bw; 20% [w/v] in sterile saline) or a saline vehicle by ip injection using a 22G needle.

Duration of treatment / exposure:

single or 15 consecutive days

Frequency of treatment:

daily

Post exposure period:

6 hours or 15 days

Doses / concentrations

Remarks:

Doses / Concentrations:
2 g/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

Three rabbits and primates were used in each treatment group. Four and five mice were used in each group for the acute and chronic studies, respectively.

Control animals:

yes, concurrent vehicle

Positive control(s):

KBrO3
- Justification for choice of positive control(s): is a known renal carcinogen
- Route of administration: i.p.
- Doses / concentrations: 100 mg/kg bw at a fixed volume of 0.1 mL/10g bw

Examinations

Tissues and cell types examined:

DNA from spleen and bone marrow

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The effect of a Iimit dose of 2.0 g/kg bw MeOH based on guidelines established for the comet assay developed in accordance with the in vivo genetic toxicology guidelines of the Organization for Econornic Co-operation and Development (OECD) were studied.

METHOD OF ANALYSIS: DNA was isolated using DNAzol, a novel guanidine-detergent lysing solution that hydrolyzes RNA and allows for the selective precipitation of DNA from cell lysates. 8-oxodG and dG were analysed via HPLC system. Lipid peroxidation in bone marrow and spleen homogenates was determined by measuring the Ievels of HNE-His protein adducts.

Statistics:

Statistical analysis was performed using GraphPad Instat Version 3.05 (GraphPad Software, lnc., San Diego, CA). Experiments comparing two groups were analyzed by unpaired t tests and multiple comparisons were anaJyzed by one-way ANOVA followed by a Tukey post-test. The Ievel of significance was set at P<0.05.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not examined

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

No increase in oxidative DNA damage was observed in bone marrow or spleen at 6 h following exposure to MeOH (2.0g/kg bw ip) in mice, rabbits,
or primates. Similarly, no increase in oxidative DNA damage was observed in bone marrow or spleen 24 h following exposure to a single dose of MeOH (2.0g/kg bw ip), or following 15 consecutive daily doses of 2.0g/kg bw ip MeOH in CD-1 mice. No increase in HNE-His protein adducts was observed in bone marrow or spleen at 6 h following exposure to MeOH (2.0 g/kg bw ip) in primates. MeOH exposure (2.0 g/kg bw ip) increased HNE-His protein adducts 1.4-fold 6 h post-dose in bone marrow of mice, with adduct Ievels returning to basal values within 24 h. No increases in HNE-His protein adducts were observed in spleen of mice or bone marrow of rabbits following MeOH exposure (2.0 g/kg bw ip). MeOH exposure (2.0 g/kg bw ip) increased HNE-His protein adducts 1.5-fold 6 h post-dose in spleen of rabbits.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Taken together these observations suggest that it is unlikely that exposure to MeOH would initiate Iymphomas, particularly in humans, via formation
of mutagenic oxidative DNA lesions.