Abstracts

#57 Impact of allergen challenge on the expression of cyclooxygenase in the murine lungs.


Sandra M. K. Ragheb, University of Manitoba; Aruni Jha, University of Manitoba and Children’s Hospital Research Institute of Manitoba; Sujata Basu, University of Manitoba and Children’s Hospital Research Institute of Manitoba; Gerald Stelmack, University of Manitoba and Children’s Hospital Research Institute of Manitoba; Jacqueline Schwartz, University of Manitoba and Children’s Hospital Research Institute of Manitoba; Andrew Halayko, University of Manitoba and Children’s Hospital Research Institute of Manitoba


Introduction

Cyclooxygenases (Cox)-1&2 are implicated in the pathogenesis of various diseases, including asthma, a chronic inflammatory disorder of the airways. House dust mite (HDM) challenge of the lungs induces a concentration-dependent increase in the influx of inflammatory cells in murine lungs. Thus, we hypothesize that HDM challenge will increase Cox-1&2 expression in mouse lungs.


Methods

Paraffin embedded/ flash frozen lungs from 6-8wks old female Balb/c mice challenged with 6, 12 or 25μg HDM/day for 2-wks (5days/wk) were used for tissue histology, to assess lung inflammation (H&E staining) and goblet cell hyperplasia (PAS staining). Cox-1&2 abundance was assessed in the lungs by immunohistochemistry (IHC) and immunoblotting.


Results

All concentrations of HDM challenge stimulated immune cell influx to the lung tissue by >3-fold (p<0.01).


Conclusion

Cox-1&2 are constitutively expressed in airway epithelial cells of the mouse lung. HDM challenge enhanced Cox-1 expression irrespective of concentration but Cox-2 expression was progressively lost with increasing HDM concentration. Goblet cell hyperplasia correlated with the concentration of HDM challenge. The results suggest that Cox-1 and 2 are distinctly modulated by allergen challenge and could differentially contribute to lung pathophysiology.