Down-regulation of endogenous hydrogen sulphide pathway in nasal mucosa of allergic rhinitis in guinea pigs

Background: The present study was designed to explore the possible changes in endogenous hydrogen sulphide (H2S), a novel gasotransmitter, on the pathogenesis of allergic rhinitis (AR). Methods: AR guinea pig model was established by nasal ovalbumin sensitisation. Guinea pigs were divided into four groups: Saline control, AR sensitised, sodium hydrosulphide (NaHS) treated, and propargylglycine (PPG) treated group. The frequency of sneezing and nose rubbing was recorded. Leukocyte infiltration in nasal lavage fluid (NLF) and plasma H2S level were measured. Expression of Cystathionine-beta-synthase (CBS) and Cystathionine-gamma-lyase (CSE) mRNA as H2S-producing enzymes in nasal mucosa was determined by real time Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). Results: The frequency of sneezing and nose rubbing, and levels of leukocyte infiltration in NLF were higher than those of control (P < 0.01), but plasma H2S in sensitised guinea pigs was lower than those of control (P < 0.05). From the results of RT-PCR, it was found that the expression of CSE was higher than CBS in nasal mucosa, and in sensitised guinea pigs it was tower than that of control (P < 0.05). NaHS successfully increased the level of H2S and alleviated the symptoms of AR accompanied by up-regulation of CSE as compared with AR group (P < 0.05). PPG significantly suppressed the expression of CSE and decreased the H2S level, yet also aggravated the symptoms of AR. Conclusion: H2S level may be negatively correlated with the process of inflammation and positively correlated with expression of CSE in nasal mucosa. The endogenous H2S pathway is down-regulated in AR. (C) 2008 SEICAP. Published by Elsevier Espana, S.L. All rights reserved.