Objective: To study the effect of carbon monoxide (CO) on hydrogen sulfide (H2S) in guinea pigs with allergic rhinitis (AR) through intervention treatment.
Methods: AR model in guinea pigs was established by using ovalbumin. The animals were divided into three groups. Group one was sensitized continuously by ovalbumin, group two was treated with Hemin as induction group, and group three was treated with zinc protoporphyrin (ZnPP) as suppression group. The guinea pigs treated with saline were used as control. The behavior science scores, eotaxin concentration of nasal lavage, IgE in blood serum were recorded, and the plasma concentrations of CO and H2S were determined, then the expression of hemeoxygenase (HO)-1, cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) were measured in nasal mucosa by fluorescent quantitative RT-PCR.
Results: The behavior science scores, concentration of eotaxin in nasal lavage, IgE in blood serum and concentration of CO in plasma of sensitized group were higher than those of control (P<0.01), and the expression of HO-1 in nasal mucosa was also higher than control [(7.61+/-2.80)x10(-3) vs (2.32+/-1.14)x10(-3), P<0.05]. All these items were higher when treated with Hemin and lower when treated with ZnPP (P<0.05). The concentration of H2S in plasma was lower than control with significant differences [(14.80+/-1.60) micromol/L vs (18.90+/-1.00) micromol/L, P<0.01], the expression of CSE was also lower than control (P<0.05), and both of them were lower with Hemin induced and higher with ZnPP (P<0.05). The expression of CBS was very low and had no significant differences between groups (P>0.05), so it indicated that the CSE was the key enzyme for endogenous H2S product in nasal mucosa. Moreover the concentration of H2S was negatively correlated with CO (r=-0.702, P<0.001).
Conclusions: Endogenous CO and H2S play a significant role in the pathogenesis of AR, and HO-1 and CSE are the main speed-relate enzymes respectively. The H2S is also influenced by CO.