Potentiation of allergic bronchoconstriction by repeated exposure to formaldehyde in guinea-pigs in vivo.

Abstract

BACKGROUND:

Indoor formaldehyde (FA) might worsen allergies and be an underlying factor for the increasing incidence and severity of asthma; the exact mechanism, however, remains unclear.

OBJECTIVE:

The present study examined the effects of repeated exposure to FA on methacholine- and antigen-induced bronchoconstriction in guinea-pigs in vivo.

METHODS:

First, non-sensitized guinea-pigs were transnasally treated with 0.1 or 1.0% FA or saline three times a week for 6 weeks, and increasing concentrations of methacholine (50, 100, and 200 microg/mL) were inhaled at 5-min intervals. Second, guinea-pigs pre-treated with transnasal administration of FA or saline using the same protocol were passively sensitized with anti-ovalbumin (OA) serum 7 days before antigen challenge. Third, guinea-pigs were actively sensitized with OA and pre-treated with transnasal administration of FA or saline using the same protocol. The lateral pressure of the tracheal tube (Pao) was measured under anesthesia and artificial ventilation.

RESULTS:

The antigen-induced increase in Pao in actively sensitized guinea-pigs was significantly potentiated by FA exposure in a dose-dependent manner. The dose-response curve of the methacholine-induced increase in Pao in non-sensitized guinea-pigs or of the antigen-induced increase in Pao in passively sensitized guinea-pigs was not altered by FA exposure. Transnasal administration of FA significantly increased the serum anti-OA homocytotropic antibody titre (IgG) as measured by the passive cutaneous anaphylaxis reaction in actively sensitized guinea-pigs.

CONCLUSION:

The results suggest that repeated exposure to FA worsens allergic bronchoconstriction through enhancing antigen sensitization.

• Authors: T Kita, M Fujimura, S Myou, Y Ishiura, M Abo, N Katayama, M Nishitsuji, Y Yoshimi, S Nomura, Y Oribe, S Nakao
• Journal: Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology (Clin Exp Allergy) Vol. 33 Issue 12 Pg. 1747-53 (Dec 2003) ISSN: 0954-7894 [Print] England
• PMID: 14656365 (Publication Type: Journal Article)

Chemical References

• Allergens
• Antibodies
• Bronchoconstrictor Agents
• Fixatives
• Immunoglobulin G
• Methacholine Chloride
• Formaldehyde
• Immunoglobulin E
• Ovalbumin

Topics

• Allergens
• Animals
• Antibodies (blood)
• Bronchial Hyperreactivity (chemically induced)
• Bronchoconstrictor Agents
• Fixatives (toxicity)
• Formaldehyde (toxicity)
• Guinea Pigs
• Hypersensitivity (immunology)
• Immunoglobulin E (blood)
• Immunoglobulin G (blood)
• Male
• Methacholine Chloride
• Ovalbumin (immunology)
• Passive Cutaneous Anaphylaxis