The Synergistic Effects And Mechanism Of Ciclesonide On Formoterol Dilating Bronchoconstraction In The Guinea Pigs

Background and objective:Formoterol is a long acting β2 adrenoceptor agonist which is used as a bronchodilator agent in asthma and chronic obstructive pulmonary disease.Ciclesonide is an anti-inflammatory inhaled corticosteroids,which is used as a anti-inflammatory medication in asthma.This study is to investigate the potential synergistic effect of formoterol and ciclesonide in vitro and in vivo,and preliminarily study the synergistic mechanismMethods:Inn vivo:Antagonist produces a inhibition of Histamine-induced bronchoconstriction.Lung resistance(RL)and dynamic lung compliance(Cdyn)changes induced by Histamine were investigated.In experiments,we evaluate the antagonist(Ciclesonide,Formoterol and Ciclesonide and Formoterol in combination)potency and the offset of action of contractile response to HistamineIn vitro:1)The whole trachea was excised from Hartley guinea-pigs(250～350 g),and cut into four transverse preparations.After an equilibration period of 60min,carbachol was administered to preparations at a concentration that in preliminary experiments had been shown to produce 80-90%of maximal contraction.Data were recorded by means of a MedLab system.Antagonist(Ciclesonide,Formoterol and Ciclesonide and Formoterol in combination)was administered to carbachol-precontracted preparations and left in contact with the tissue until complete inhibition was attained.In experiments,we evaluate the antagonist potency and the offset of action of contractile response to carbachol2)The whole trachea was excised from Hartley guinea-pigs(250～350 g),took four pieces of trachea,weighted 200mg per piece.After 20 min incubation in K-H acid with the drugs(Ciclesonide,Formoterol and Ciclesonide and Formoterol in combination),the trachea was then immediately homogenized in 1.5 ml ice-cold 5%trichloroacetic acid,and centrifuged at 3000 g for 20 min.The supernatants were washed with five volumes of water-saturated diethyl ether for three times.After drying,the extracts were stored-70℃until the cAMP assay.Tissue cAMP accumulation was measured with a cAMP Enzyme linked immune sorbent assay kit.Results:In vivo1)Compared with control group,formoterol(9μg/kg)and ciclesonide(0.6 mg/kg)significantly inhibited increase of lung resistance(RL)and decrease of dynamic clung compliance(Cdyn)induced by Histamine2)Compared with control group,formoterol(9μg/kg)and ciclesonide(0.6 mg/kg)in combination significantly inhibited increase of RL and decrease of Cdyn induced by Histamine.The capabilities of inhibiting the increase of RL and decrease of Cdyn of formoterol and ciclesonide in combination was significantly better than formoterol and ciclesonide alone when the concentration of Histamine was 1.2 mg/mLIn vitro:1)Formoterol produced concentration-dependent inhibition of carbachol-induced tonic contraction.And ciclesonide,which had only a minor effect on histamine induced bronchoconstriction itself,markedly increased the protective effect of formoterol in a synergistic manner at the dose of 3 × 10-6 mol/L and 10-5 mol/L2)Ciclesonide(10-8M)showed no effect on the cAMP level in guinea pig trachea.And formoterol(10-8 M)significantly increased the cAMP level in guinea pig trachea.In the presence of Ciclesonide(10-8 M),the effect of formoterol(10-8 M)was significantly increasedConclusion:1)Combined use of formoterol and ciclesonide synergistically relieved the Histamine-induced bronchoconstriction.2)Combined use of formoterol and ciclesonide synergistically relieved carbachol-induced tonic contraction3)Combined use of formoterol and ciclesonide synergistically increased the cAMP level in guinea pig trachea.4)The synergistical enhancement may be mediated through the cAMP release.