Tissue-type plasminogen activator depletion affects the nasal mucosa matrix reconstruction in allergic rhinitis mice.

BACKGROUND The present study was designed to assess the function of tissue plasminogen activator (t-PA) expression in allergic rhinitis. METHODS Age-matched t-PA gene knock out (t-PA(-/-)) and wild type (WT) mice were sensitised four times, and then challenged for six weeks with ovalbumin. The controls were treated with saline instead of ovalbumin. The structural change in the nasal mucosa was investigated with haematoxylin and eosin stain and van Gieson staining. u-PA (urokinase-type plasminogen activator) and PAI-1 (plasminogen activator inhibitor) gene expression were measured by real time PCR. Matrix metalloproteinase-9 (MMP-9) expression was tested with Western blotting and with real time PCR. RESULTS After ovalbumin challenge for six weeks, compared with the WT group, t-PA depletion increased collagen deposition and gland hyperplasia. u-PA and PAI-1 gene expression increased both in t-PA(-/-) and in WT mice after ovalbumin treatment. MMP-9 expression decreased greatly after ovalbumin challenge in t-PA(-/-) mice. CONCLUSION t-PA affects the nasal mucosa matrix reconstruction process in allergic rhinitis, with which MMP-9 is involved.