Related Experiment Video
Updated: May 20, 2026
Intra-tracheal Administration of Haemophilus influenzae in Mouse Models to Study Airway Inflammation
Published on: March 2, 2016
Inflammatory airway responses by nasal inoculation of suspended particulate matter in NC/Nga mice
Keiki Ogino1, Noriko Takahashi, Masayuki Kubo
1Department of Public Health, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1, Shikata-cho, Kita-ku, Okayama, Japan.
Abstract:
To evaluate the allergic effect of airborne particulate matter (PM) on the airway, separated soluble supernatant (Sup) and insoluble precipitate (Pre) in suspended PM were inoculated into NC/Nga mice with a high sensitivity for mite allergens. Sup, Pre, or both Sup and Pre with or without pronase treatment were inoculated via the nasal route five times for sensitization and a challenge inoculation on the 11th day in NC/Nga mice. On the 14th day, mice were examined for airway hyperresponsiveness (AHR), bronchoalveolar lavage fluid (BALF) cell count, mRNA expression of Th1 and Th2 cytokines in the lung tissue, and histopathology. Synergistic effects of Sup and Pre were observed as increases in AHR and a histopathological change of Periodic acid-Schiff (PAS) staining. Increases in neutrophils, macrophages, and lymphocytes of BALF cells were dependent on Pre. The expression of IL-4 mRNA was increased by Sup, and those of IL-5 mRNA and Il-13 mRNA was increased by Sup and Pre. Augmented AHR, mRNA expression of IL-4, peribronchial inflammation, and PAS staining by Sup plus Pre were attenuated by treatment of Sup with pronase to digest proteins. These results suggest that some proteins of ambient PM may be important environmental factors for AHR and airway inflammation with the aid of insoluble particulates, although some soluble factors such as endotoxins cannot be ruled out.
Insights
Airborne particulate matter (PM) proteins, aided by insoluble particles, can worsen airway hyperresponsiveness and inflammation. Pronase treatment suggests proteins are key factors in these allergic effects.
Area of Science:
- Environmental Health
- Immunology
- Toxicology
Background:
- Airborne particulate matter (PM) is a complex mixture with potential allergenic effects.
- Understanding the specific components of PM responsible for airway inflammation is crucial for public health.
Purpose of the Study:
- To investigate the distinct allergic effects of soluble (Sup) and insoluble (Pre) fractions of PM on airway responses.
- To determine the role of PM proteins in exacerbating airway hyperresponsiveness (AHR) and inflammation.
Main Methods:
- NC/Nga mice, sensitive to allergens, were intranasally inoculated with PM fractions (Sup, Pre, or both) with or without pronase treatment.
- Evaluated airway hyperresponsiveness (AHR), bronchoalveolar lavage fluid (BALF) cell counts, cytokine mRNA expression (Th1/Th2), and lung histopathology.
Main Results:
- Synergistic effects of Sup and Pre increased AHR and caused histopathological changes (PAS staining).
- Insoluble PM (Pre) increased neutrophils, macrophages, and lymphocytes in BALF.
- Soluble PM (Sup) increased IL-4 mRNA, while both Sup and Pre increased IL-5 and IL-13 mRNA.
- Pronase treatment, which digests proteins, attenuated AHR, inflammation, and PAS staining induced by Sup plus Pre.
Conclusions:
- Proteins within ambient PM, in conjunction with insoluble particulates, are significant contributors to AHR and airway inflammation.
- While protein components are implicated, soluble factors like endotoxins cannot be entirely excluded as contributing factors.
