Antiasthmatic Effect Of Dct And Mechanisms

Objective:Dingchuantang(DCT) from "Many Prescription of Health Cultiveation" is a famous prescription to cure cough and dyspnea by the exterior tightened by pathogenic wind-cold and accumulation phlegm-heat in the interior. The principal of the prescription is to disperse the inhibited Lung-Qi, low adverse-rising Lung-Qi and cool eliminating phlegm. DCT has been used in clinic in the past handreds years as a effective prescription. In order to explore the mechanisms of DCT in relieving asthma, This experiment has studied the actions of reducing airway hyperresponsiveness of DCT.Methods:1. Observing the latent period of asthma on guinea pigs caused by histamine and acetylcholine.2. Determining the abnormal serum IgE and IgG contents of allergic shock model on guinea pigs caused by eggwhite.3. Examining the abnormal serum cAMP and cGMP contents of allergic asthma model caused by 4%egg-albumin-normal saline and 4% aluminum hydroxide gel.4.Inspecting the inhibition of isolated tracheal constraction on guinea pigs caused by histamine and acetylcholine.5. Investigating the action ofβ-receptor on guinea pigs tracheal smooth muscle.Results:1. The latent period of asthma was obviousely prolong on guinea pigs prevented by DCT, and had significant difference when compaired with normal group(P＜0.01) and Dexamethasone Tablet group(P＞0.05).2. DCT could prolong the latent period of asthma caused by egg-white. The DCT group's content of abnormal serum IgE was lower and that of IgG was higher, both of them were significant difference with allergic shock model group(P＜0.05, P＜0.05), and there were no significant difference between Dexamethasone Tablets group(P＞0.05, P＞0.05).3. Compaired with allergic asthma model group, the contents of cGMP decreased(P＜0.05), the content of cAMP and the ratio of cAMP and cGMP increased((P＜0.05, P＜0.05).4. DCT could markedly inhibit the contraction of isolated tracheal smooth muscle of guinea pigs induced by histamine and acetylcholine, the percentage of inhibition respectively were 100.79±15.40, 89.35±6.05. 5. DCT could markedly relieve the contraction of isolated tracheal smooth muscle of guinea pigs, but this function could be blocked by Timolol.Conclusion:DCT had obvious effects of relieving asthma on asthmaic guinea pigs, inhibite the contraction of isolated tracheal smooth muscle, its machanism of reducing airway hyperresponsiveness probably were as follows:1. Due to regulating the immune function, DCT could decrease abnormal serum IgE and increase IgG on allergic shock model of guinea pigs.2. Due to decreasing the contents of serum cGMP, increasing the contents of serum cAMP and stabilizing the ratio of cAMP and cGMP, DCT could brought on a result in relieve asthma.3. Due to being a adrenomimetic, DCT could diastolizate the bronchus smooth muscle and reduce the bronchial contraction.4. Due to exciting onlyβ-receptor on bronchus smooth muscle, DCT could diastolizate the bronchus smooth muscle and had a function of bronchi spasmolysis.