Registration Dossier

Administrative data

Endpoint:
respiratory sensitisation: in vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented study.

Data source

Reference
Reference Type:
publication
Title:
Phthalate treatment does not influence levels of IgE or Th2 cytokines in B6C3F1 mice
Author:
Butala JH, David RM, Gans G, McKee RH, Guo TL, Peachee VL, White KL Jr.
Year:
2004
Bibliographic source:
Toxicology. 2004 Sep 1;201(1-3):77-85.

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Topical application (and challenge) of test substances to mice followed by measurements of total serum IgE. In addition, auricular lymph nodes were harvested for measurement of IL-4 and IL-13 proteins and their corresponding messenger RNAs. Because skin absorption of high molecular weight phthalates is limited, liver weight increase, a measure of peroxisomal proliferation, was monitored to assure that internal dosing had been achieved.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
not specified

Test system

Route of induction exposure:
dermal
Route of challenge exposure:
other: application to ear
Vehicle:
unchanged (no vehicle)
Concentration:
undiluted, 50 ul/flank
No. of animals per dose:
10
Positive control substance(s):
trimellitic anhydride (TMA)
Negative control substance(s):
2,4-dinitrochlorobenzene (DNCB)

Results and discussion

Results:
The mice tolerated the treatment well; all animals survived, and there were no significant differences in body weight. Liver weights of DINP- treated mice were significantly elevated with respect to control at the P < 0.05 level. Total serum IgE levels were significantly increased by treatment with the positive control, TMA. There were also smaller but still significant increases in IgE levels in mice treated with DNCB. The appropriate responses with the reference compounds demonstrated the specificity of the assay system. In contrast to these materials, total IgE levels in serum from mice treated with the DINP were not significantly different from control values. The assessment of IL-4 and IL-13 levels in cultured lymph node cells revealed a large and statistically significant increase in cells from mice treated with TMA. IL-4 and IL-13 levels were also elevated in the DNCB-treated groups in some situations, but were not significantly different from control values. Neither IL-4 nor IL-13 was elevated in cells from control group mice or mice treated with DINP. Similarly, TMA significantly increased IL-4 and IL-13 mRNA levels in lymph node cells. DNCB treatment increased IL-4 and IL-13 mRNA in some cases, but these differences, while sometimes statistically significant, were well below levels associated with TMA treatment. DINP treatment had no effect on IL-4 or IL-13 mRNA levels.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Executive summary:

Bronchial asthma is mediated, in part, by the immunoregulatory cytokines interleukins 4 and 13 (IL-4 and IL-13). These cytokines stimulate IgE synthesis that in turn is associated with airway hyper-responsiveness. Compounds that stimulate IgE synthesis and elicit bronchial reactivity are generally considered to be respiratory sensitizers. To address this question, topical application (and challenge) of test substances (DINP included) to mice followed by measurements of total serum IgE was performed. In addition, auricular lymph nodes were harvested for measurement of IL-4 and IL-13 proteins and their corresponding messenger RNAs. Because skin absorption of high molecular weight phthalates is limited, liver weight increase, a measure of peroxisomal proliferation, was monitored to assure that internal dosing had been achieved. ELISA and RNAse protection assays demonstrated that DINP treatment did not significantly affect IgE, IL-4, or IL-13 levels. Similarly, IL-4 and IL-13 mRNA levels were not elevated. In contrast, all of these were significantly elevated by trimellitic anhydride (TMA), a respiratory sensitizer used as the positive control in this assay. Another control, dinitrochlorobenzene (DNCB), a contact sensitizer, also responded as expected, producing smaller but statistically significant increases in IgE and in mRNA for IL-4 and IL-13 but not in the levels of these cytokines. In summary, treatment with DINP did not result in significant elevations indicating that DINP has little, if any, potential to produce anti-body-mediated respiratory allergy.