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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Slightly modified LLNA study with no information on GLP status

Data source

Reference
Reference Type:
publication
Title:
Examination of the Local Lymph Node Assay for Use in Contact Sensitization Risk Assessment
Author:
Gerberick GF, House RV, Fletcher ER, Ryan CA
Year:
1992
Bibliographic source:
Fundam. & Appl. Toxicol., 19:438-445

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Remarks:
Application of test substance on 4 days, with evaluation on Day 5
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): methyl salicylate supplied by Sigma Chemical Co. (St Louis, MO)
- Analytical purity: 90-95%

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Jackson Labs (Bar Harbor ME) or NCI (Fredrick, MD)
- Age at study initiation: 6-9 weeks
- Weight at study initiation: no data
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
no data

IN-LIFE DATES: no data

Study design: in vivo (LLNA)

Vehicle:
other: acetone
Concentration:
1, 2.5, 5%
No. of animals per dose:
5
Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: SI >= 2 and statistically significant from vehicle-treated control (p>0.01)
Positive control substance(s):
other: 1-chloro-2,4,6-trinitrobenzene
Statistics:
Intergroup comparisons based on analysis of variance or distribution free methods. Bartlett's test of homogeneity of variance, and least significance difference or Wilcoxon's rank sum test.

Results and discussion

Positive control results:
TNCB dpm-fold increase: 0.01%: 18.0; 0.05%: 80.3; 0.10%: 103.3

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: acetone: 1.0 MeS: 1%: 0.8; 2.5% :0.8; 5%: 0.8
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: acetone: 455 MeS: 1%: 385; 2.5%: 380; 5%: 380

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
Under the conditions of the present assay, at the low concentrations tested, MeS was shown not to have sensitization potential.
Executive summary:

Methyl salicylate was one of 17 chemicals tested in an examination of the LLNA assay for use in contact sensitization risk assessment (Gerberick, 1992).

In a slightly midified LLNA protocol, test items were applied on both surfaces of ears of 5 femaleCBA/J mice per group (25 µl/ear) for four consecutive days (Days 1, 2, 3 and 4). MeS was tested at concentrations of 0, 1, 2.5 and 5% in acetone. On Day 5, the cell proliferation in the local lymph nodes was measured for each individual mouse by incorporation of tritiated methyl thymidine ([3H]TdR). The values obtained were used to calculate stimulation indices (SI).

A chemical was considered positive (sensitizer) in this assay if exposure to at least one concentration resulted in a 2-fold or greater increase in [3H]TdR, expressed as disintegrations per minute (dpm) provided that this mean dpn value was statistically different from vehicle-treated mice (p=< 0.01). Chemicals wee considered to be moderate to strong sensitizers if the increase was >30-fold and weak to moderate sensitiser if the increase was 2-30-fold over vehicle-treated mice.

Stimulation index value for MeS was 0.8 at each of the treatment concentrations of 1, 2.5 and 5%.

Under the conditions of this assay, MeS tested in acetone, was considered not to be a sensitizer, however the concentrations tested were not high enough to exclude the possibility of sensitization at higher substance concentrations.