Objective: To explore the expression and pathogenic mechanism of heme oxygenase-1(HO-1) in asthma.
Methods: Two groups of guinea pigs (10 in each) were treated with the specific stimulator(hemin) and inhibitor(Sn-PP) of HO-1 respectively. Their effects on the levels of HO-1 activity, COHb, cGMP and IgE in serum or blood and lung tissues were compared with each other. Acute asthmatic group (AAG), dexamethasone-prevented group(DPG), stable asthmatic group, ovalbumin-sensitized group and normal control group(NCG) were also included. Lung tissues of tested animals were pathologically observed and immunohistochemically stained.
Results: In the AAG and hemin stimulated group, the levels of COHb, cGMP and IgE were significantly increased with higher levels of activity and expression of HO-1 protein compared with the NCG (t = 4.575-10.188, P < 0.01). In DPG and Sn-PP inhibited groups, however, all measured parameters were markedly reduced compared with the AAG(P < 0.01). The other groups were normal.
Conclusions: The increased production and activity of HO-1 resulted in increases of endogenous CO and cGMP and promoted inflammation and immunoreaction in asthma.