Characteristics of lower airway inflammatory changes in the minimal persistent inflammation of allergic rhinitis in mice

ABSTRACT

Objective: This study aims to establish an experimental mouse model of minimal persistent inflammation (MPI), observe the features of inflammation and hyper-responsiveness of the upper/lower airways, and explore the relationship between inflammation and hyper-responsiveness in the upper/lower airways. Methods: Sixty-four female BALB/c mice were randomly divided into four groups: allergic rhinitis (AR) group as positive control, MPI group, negative control group and blank control group. Mice were given high and low-concentrated ovalbumin solution after basic and intensive sensitization to establish AR model and MPI model. Nasal mucosa and lung tissues were stained to observe eosinophil infiltration, goblet cell hyperplasia, and expression of intercellular adhesion molecule 1 (ICAM-1). Airway hyper-responsiveness was assessed. Levels of specific immunoglobulin E (sIgE), interleukin (IL)-4 and IL-5 in peripheral blood, nasal lavage fluid (NLF), and bronchoalveolar lavage fluid (BALF) were detected by Enzyme-linked immunosorbent assay. Results: The eosinophil infiltration and expression of ICAM-1 on nasal mucosa and in lung tissues in the AR and MPI groups were significantly elevated compared to control groups. Goblet cells count increased only in the nasal mucosa and not in lung tissues. Eosinophil and neutrophil count of NLF and BALF in the AR and MPI groups increased significantly compared to control groups. Level of IL-4 did not increase significantly, but sIgE and IL-5 did. Conclusions: Mice in the MPI status exhibits lower airway inflammation and hyper-responsiveness with increase in eosinophil count, goblet cells, ICAM-1, IL-4, and IL-5. These results provide further evidence for the importance of MPI of AR in lower airway diseases.

KEYWORDS:

• Allergic rhinitis
• minimal persistent inflammation
• lower airway inflammation
• hyper-responsiveness

Acknowledgements

The authors would like to acknowledge the contributions of Dr. Yang Bi and Dr. Xiaohua Liang, who both provided input into the study design, helped interpret the results, and provided comments on prior drafts of this manuscript.

Declaration of interest

This work was supported by the project of Chongqing Municipal Health Bureau, China, grant number 2013-2-059. The authors are grateful to all study participants. The authors declare that they have no conflict of interest and manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed.

Sincerely,

Zhou Fu

Pediatrics Research Institute,

Ministry of Education Key Laboratory of Child Develop-

 ment and Disorders

Children's Hospital, Chongqing Medical University

Chongqing 400014, China

Phone & Fax: [phone]

E-mail: [email protected].

Funding

Chongqing People's Municipal Government source. This work was supported by the project of Chongqing Municipal Health Bureau (2013-2-059).