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Open Access Research article

Food allergy alters jejunal circular muscle contractility and induces local inflammatory cytokine expression in a mouse model

Jørgen Valeur12, Jani Lappalainen3, Hannu Rita4, Aung Htun Lin1, Petri T Kovanen3, Arnold Berstad12, Kari K Eklund35 and Kirsi Vaali1*

Author Affiliations

1 Institute of Medicine, University of Bergen, Bergen, Norway

2 Department of Medicine, Haukeland University Hospital, Bergen, Norway

3 Wihuri Research Institute, Helsinki, Finland

4 Faculty of Agriculture and Forestry, Statistics and Methodology, University of Helsinki, Helsinki, Finland

5 Department of Rheumatology, Helsinki University Central Hospital, Helsinki, Finland

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BMC Gastroenterology 2009, 9:33  doi:10.1186/1471-230X-9-33

Published: 18 May 2009

Abstract

Background

We hypothesized that food allergy causes a state of non-specific jejunal dysmotility. This was tested in a mouse model.

Methods

Balb/c mice were epicutaneously sensitized with ovalbumin and challenged with 10 intragastric ovalbumin administrations every second day. Smooth muscle contractility of isolated circular jejunal sections was studied in organ bath with increasing concentrations of carbamylcholine chloride (carbachol). Smooth muscle layer thickness and mast cell protease-1 (MMCP-1) positive cell density were assayed histologically. Serum MMCP-1 and immunoglobulins were quantified by ELISA, and mRNA expressions of IFN-γ, IL-4, IL-6 and TGFβ-1 from jejunal and ileal tissue segments were analyzed with quantitative real-time PCR.

Results

Ovalbumin-specific serum IgE correlated with jejunal MMCP-1+ cell density. In the allergic mice, higher concentrations of carbachol were required to reach submaximal muscular stimulation, particularly in preparations derived from mice with diarrhoea. Decreased sensitivity to carbachol was associated with increased expression of IL-4 and IL-6 mRNA in jejunum. Smooth muscle layer thickness, as well as mRNA of IFN-γ and TGF-β1 remained unchanged.

Conclusion

In this mouse model of food allergy, we demonstrated a decreased response to a muscarinic agonist, and increased levels of proinflammatory IL-6 and Th2-related IL-4, but not Th1-related IFN-γ mRNAs in jejunum. IgE levels in serum correlated with the number of jejunal MMCP-1+ cells, and predicted diarrhoea. Overall, these changes may reflect a protective mechanism of the gut in food allergy.