Registration Dossier

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Influence of irritants on lymph mode cell proliferation and the detection of contact sensitivity to metal salts in the local lymph mode assay
Author:
Ikarashi Y, Tsukamoto Y, Tsuchiya T and Nakamura A
Year:
1993
Bibliographic source:
Contact Dermatitis 29, 128-132

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
not specified
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test article name : DMSO
Source: Wako Pure Chemical Industries, Osaka, Japan
Batch number: no data
Purity: no data

In vivo test system

Test animals

Species:
mouse
Strain:
Balb/c
Sex:
not specified
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Japan SLC Inc. Shizuoka, Japan
- Age at study initiation: 6-8 weeks old
no other data

Study design: in vivo (LLNA)

Vehicle:
other: water
Concentration:
Induction 0, 20, 50, 100 % active substance open epicutaneous
No. of animals per dose:
3 mice per dose
Details on study design:
Groups of mice (n=3) were exposed topically to 25 µl of various concentrations of DMSO in water or an equal volume of water on the dorsum of both ears.
Treatment was performed daily for 3 consecutive days. 

On the day following the final application, the draining auricular lymph nodes were exised and pooled for each experimental group. A single-cell suspension of LNC was prepared by mechanical disaggregation through 200-mesh stainless-steel gauze. Cells were washed once with phosphate-buffered saline (pH 7.2) and resuspended in RPMI-1640 culture medium supplemented with 25 mM N-2-hydroxvethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer, 100 units/ml penicillin, 100 µg/ml streptomycin and 10% fetal calf serum at a concentration of 5 x 10e6 cells/ml. The cell suspensions (200 µl) were seeded into 96-well microplates (5 wells per group) and cultured for 24 h at 37°C in a humiditied atmosphere of 5% CO2 in air with 0.5 µCi [methyl-3H] thymidine (3HTdR). Culture was terminated by automatic cell harvesting and 3HTdR incorporation was determined by liquid scintillation counting. 

A stimulation index (Si), increase in 3HTdR incorporation relative to vehicle-treated control was derived for each concentration of test chemical.
Positive control substance(s):
other: potassium dichromate and nickel sulfate

Results and discussion

Positive control results:
An increase in LNC proliferation was observed following exposure to potassium dichromate et nickel sulfate using DMSO as a vehicle.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: DMSO : 2.65 at 100%
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: water alone: 1.36+/-0.27 cpm

Any other information on results incl. tables

DMSO: Exposure of groups of 3 mice to pure DMSO (concentration 20 and 50 % being ineffective) induced a small increase(approximately 2.65-fold) in LNC proliferation compared withthe water-solution treated group.

Treatment

HTdR incorporation (mean cpm+/-SD 10e3)

SI

H20

1,36

±

0,27

-

20% DMSO

0,38

±

0,17

1,01

50% DMSO

1,6

±

0,05

1,18

100% DMSO

3,61

±

0,24

2,65

 

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
DMSO is not considered as sensitizing.
Executive summary:

The delayed contact hypersensitivity of Dimethylsulfoxide (DMSO) was evaluated in mice according to a protocol similar to the OECD N° 429 Guideline (Local Lymph Node Assay).

During the induction phase, DMSO or water were applied over the ears (25 μL per ear) for 3 consecutive days (days 1, 2 and 3) in groups of 3 CBA/J mice.

On the days following the final application, the proliferation of lymphocytes in the lymph node draining the application site was measured by incorporation of tritiated methyl thymidine. The obtained values were used to calculate stimulation indices (SI).

No significant lymphoproliferation was observed in the DMSO-treated group. A stimulation index of 2.65 has been calculated for undiluted DMSO.

Under these experimental conditions, DMSO does not induce delayed contact hypersensitivity in the murine Local Lymph Node Assay and is not considered as sensitizing.