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Updated: Jul 19, 2026
Murine Model of Allergen Induced Asthma
Published on: May 14, 2012
Effect of montelukast on bacterial sinusitis in allergic mice
Paneez Khoury1, Fuad M Baroody, James J Klemens
1Department of Surgery, Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Illinois 60637, USA.
Background:
In mice, allergic rhinitis augments the infectious and inflammatory response to Streptococcus pneumoniae-induced sinusitis.
Objective:
To investigate the effects of cysteinyl leukotriene antagonism on the severity of bacterial infection.
Methods:
We performed 3 parallel, placebo-controlled experiments. In the first, mice were ovalbumin sensitized and ovalbumin challenged to show the effects of montelukast on the allergic inflammation; in the second, we evaluated the effect of montelukast on S. pneumoniae infection; in the third, we used mice that were both allergic and infected. Montelukast was given starting 2 days after sensitization until the day before euthanasia. One day after drug treatment began, the mice were inoculated intranasally with S. pneumoniae in the infected groups. Nasal hypersensitivity was measured with histamine challenges before the first sensitization and on the day before euthanasia. On the fifth day after infection, mice were euthanized, nasal lavage was performed, bacteria were cultured, and inflammatory cells in the sinuses were quantified.
Results:
Mice that were infected only tended toward having increased bacterial counts from nasal lavage in the montelukast-treated group. The mice that were allergic and infected experienced significantly higher bacterial counts (P < .05). All 3 montelukast treatment groups had significantly decreased eosinophil counts as well as T-lymphocyte counts.
Conclusions:
Montelukast reduces the manifestations of allergic rhinitis in mice. Surprisingly, montelukast led to an increase in bacterial growth in infected mice. This suggests an effect of the cysteinyl leukotrienes on the innate response to bacterial infection.
Insights
Montelukast reduced allergic rhinitis symptoms in mice but unexpectedly increased bacterial growth in infected mice. This suggests cysteinyl leukotrienes influence the innate immune response to bacterial infections.
Area of Science:
- Immunology
- Pharmacology
- Microbiology
Background:
- Allergic rhinitis exacerbates Streptococcus pneumoniae infection and inflammation in mice.
- Cysteinyl leukotrienes play a role in allergic inflammation.
Purpose of the Study:
- To investigate the impact of cysteinyl leukotriene antagonism on bacterial infection severity.
- To evaluate montelukast's effect on allergic rhinitis and S. pneumoniae infection in mice.
Main Methods:
- Three placebo-controlled experiments were conducted in mice: allergic inflammation, bacterial infection, and combined allergic and infected models.
- Mice received montelukast treatment, were infected with S. pneumoniae, and assessed for nasal hypersensitivity, bacterial counts, and inflammatory cell infiltration.
Main Results:
- Montelukast significantly decreased eosinophil and T-lymphocyte counts in all treatment groups.
- In allergic and infected mice, montelukast treatment led to significantly higher bacterial counts.
- Infection-only groups showed a trend toward increased bacterial counts with montelukast treatment.
Conclusions:
- Montelukast effectively reduces allergic rhinitis manifestations in a mouse model.
- Montelukast treatment surprisingly increased bacterial growth in infected mice, indicating a role for cysteinyl leukotrienes in innate immunity.
- Further research is needed to elucidate the precise mechanisms by which cysteinyl leukotrienes modulate the response to bacterial pathogens.
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