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Expression of cytokine mRNAs in mice cutaneously exposed to formaldehyde
Baohui Xu1, Kohji Aoyama, Minoru Takeuchi
1Department of Environmental Medicine, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan. xubohui@m.kufm.kagoshima-u.ac.jp
Abstract:
In this study, we have investigated the expression of cytokine mRNAs in mice cutaneously exposed to formaldehyde using semiquantitative RT-PCR. We show that formaldehyde induced the long-lasting expression of IL-4 and IFN-gamma mRNAs and the transient expression of IL-13 mRNA in mouse spleen and draining lymph nodes. The transient increases in IL-2, IL-15, IL-12p40, IL-15 and IL-18 mRNAs, but long-lasting IL-15 mRNA were only seen in the formaldehyde-exposed mouse spleen. Moreover, a weak contact hypersensitivity (CH) and the significant increases in IL-4 and IFN-gamma mRNAs were detected in the ear skin of formaldehyde-cutaneously exposed mice when rechallenged mouse ears. Furthermore, CH as measured by mouse ear swelling response was positively correlated with IL-4 and IFN-gamma mRNA levels in the challenged ears. This study thus suggests that the induction of Th1 and Th2 cytokine mRNAs, particularly IL-4 and IFN-gamma, are a common immunological feature caused by contact allergens irrespective of strong or weak contact allergens. The analysis of IL-4 and IFN-gamma mRNAs may be useful markers in establishing the novel test for predicting chemical sensitizing potentials.
Insights
Formaldehyde exposure in mice triggers long-lasting immune responses, specifically increasing interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) mRNA. These cytokine changes correlate with contact hypersensitivity, suggesting their use as biomarkers for chemical sensitization.
Area of Science:
- Immunology
- Toxicology
- Molecular Biology
Background:
- Cutaneous exposure to chemicals like formaldehyde can elicit immune responses.
- Understanding the molecular mechanisms of chemical sensitization is crucial for safety assessment.
Purpose of the Study:
- To investigate the expression of cytokine messenger RNAs (mRNAs) in mice following cutaneous exposure to formaldehyde.
- To explore the relationship between cytokine mRNA induction and contact hypersensitivity (CH).
Main Methods:
- Semiquantitative reverse transcription polymerase chain reaction (RT-PCR) was used to analyze cytokine mRNA expression.
- Mice were exposed cutaneously to formaldehyde, and immune responses were assessed in spleen, lymph nodes, and ear skin.
Main Results:
- Formaldehyde induced long-lasting expression of IL-4 and IFN-gamma mRNAs in mouse spleen and draining lymph nodes.
- Transient increases in IL-13, IL-2, IL-15, IL-12p40, and IL-18 mRNAs were observed.
- Weak contact hypersensitivity and significant increases in IL-4 and IFN-gamma mRNAs were detected in the ear skin upon rechallenge.
Conclusions:
- The induction of Th1 (IFN-gamma) and Th2 (IL-4) cytokine mRNAs is a common feature of contact allergens.
- IL-4 and IFN-gamma mRNA levels may serve as useful biomarkers for predicting chemical sensitizing potentials.