The Effect of Carvacrol on Serum Cytokines and Endothelin Levels of Ovalbumin Sensitized Guinea-Pigs

Objective(s): Different pharmacological effects of carvacrol including relaxant effect, its inhibitory effect on muscarinic and histamine (H(1)) and stimulatory effect on β-adrenoceptors have been demonstrated on guinea pig tracheal chains in previous studies. In the present study, the effect of carvacrol on blood IL-4, IFN- γ and endothelin levels of sensitized guinea pigs is examined. Materials and Methods: Five groups of guinea pigs sensitized to ovalbumin (OA) were given pure drinking water (group S), drinking water containing three concentrations of carvacrol (40, 80 and 160 µg/ml)) and dexamethasone. The blood IL-4, IFN- γ and endothelin levels of sensitized and control guinea pigs were evaluated (n=6, for all groups). Results: Blood IL-4 and IFN-γ levels (P<0.001 for both cases) as well as endothelin (P<0.01) were increased but IFN-γ/IL-4 ratio decreased (P<0.05) in sensitized animals compared to controls. The treatment of S animals by dexamethasone (P<0.01) and two higher concentrations of carvacrol (P<0.001 for both cases) significantly decreased IL-4 level. The treatment of S animals with dexamethasone did not changed IFN-γ levels but treatment with high concentration of carvacrol significantly increased its level (P<0.001). In addition, IFN-γ/IL-4 ratio was significantly increased in S groups, who were treated with dexamethasone (P<0.05) and two higher concentrations of carvacrol (P<0.001 for both cases). Treatment of S animals by dexamethasone (P<0.01) and all concentrations of carvacrol also significantly decreased endothelin level (P<0.01 to P<0.001). Conclusion: The results show that carvacrol causes the reduction of IL-4 and endothelin, but it increases IFN-γ and IFN-γ/IL-4 ratio in the blood of sensitized guinea pigs. The results also suggest more specific effect of carvacrol compared to dexamethasone due to the absence of the effect of later on IFN-γ.