OBJECTIVETo confirm the expression and distribution of aquaporin 5 (AQP5) in rat nasal mucosa of experimental allergic rhinitis and to investigate the relationship between AQP5 and allergic rhinitis.

METHODSTwenty-four healthy Wistar rats both male and female weighting 200-300 g were divided into two groups randomly, one was testing group (n = 12), the other was comparing group (n = 12). Generally sensitized rats in testing group were given repeated local booster sensitization into nasal cavity. Twelve normal rat nasal mucosa and twelve nasal mucosa from rat with allergic rhinitis were used. The distribution of AQP5 in normal rat nasal mucosa and nasal mucosa in rat with allergic rhinitis were observed by immunofluorescence technique. Furthermore, the expression of AQP5 in normal rat nasal mucosa and nasal mucosa from rat with allergic rhinitis were studied by immunohistochemical staining.

RESULTSHematoxylin and eosin staining showed that there was obvious inflammation reaction, a large quantity of glands hyperplasia and acidophils soaked in nasal mucosa from rat with allergic rhinitis. (2) Both immunofluorescence technique and immunohistochemical staining showed that the distribution of AQP5 in normal rat nasal mucosa was in accordance with that in nasal mucosa from rat with allergic rhinitis on the whole. AQP5 expressed mainly in the membrane and cytoplasm of the epithelium in the glands, ducts and cilia. (3) The statistical analysis of the immunohistochemical staining showed that the quantity of AQP5 in rat nasal mucosa with allergic rhinitis (156.37 +/- 1.93) was obviously higher than that in the normal rat nasal mucosa (178.52 +/- 1.94). There was statistical significance between the two groups (t = 28.08, P < 0.01).

CONCLUSIONSThe hypersecretion of glands has a close relationship with the high expression of AQP5 in allergic rhinitis.