OBJECTIVETo investigate the relationship between allergic rhinitis (AR) and asthma as well as the mechanisms related with it.

METHODSSixty healthy rats were randomly divided into AR group and control group. AR model was established by intraperitoneal injection of ovalbumin (OVA) and nasal challenge with OVA. Nasal mucosa and lung tissue from both groups were stained with hematoxylin-eosin (HE), alcian-blue and periodic acid-schiff (AB-PAS), respectively. At the same time, the lung tissue was studied by transmission electron microscopy (TEM). Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to examine the level of interleukin-4 (IL-4) in bronchial alveolus lavage fluid (BALF) and the expression of intercellular adhesion molecule-1 (ICAM-1) and MUC5AC in nasal and lung tissue, respectively.

RESULTSInfiltration of inflammatory cells in nasal mucosa and lung tissue of AR model in rat was evident. Cilia destruction of bronchial epithelial cells of AR model was found. The level of IL4 in BALF of AR group (58.10 +/- 7.92) pg/ml was significant higher compared with that in control group (24.66 +/- 2.07) pg/ml. The expression of ICAM-1 (0.66 +/- 0.24) and MUC5AC (0.71 +/- 0.10) in lung tissue were both significantly higher than that in control group (0.23 +/- 0.02, 0.29 +/- 0.03).

CONCLUSIONSAllergic inflammation in nasal mucosa not only leads to changes in both histopathology and immunology, but also initiates the inflammation in lower respiratory tract mainly causing the change of cytokines and mucin.