Effects Of Alpha-Terpineol Isolated From Folium Artemisiae Argyi On Airway Inflammation And Blood Th1/Th2 Balance In A Mouse Model Of Asthma

Background: Folium Artemisiae Argyi is the dry leaf of Artemisia argyi levl.et Vant., which is reported to be effective in the treatment of asthma and cough by oral and external use among the people. In 1970s, scientists in Zhejiag Medical University and Zhejiang Institute of Traditional Chinese Medicine demonstrated that the extracts of Folium Artemisiae Argyi had bronchodilatory effect through a great deal of pharmacological studies and clinical trials. This active constituent was alpha-Terpineol.Asthma is a chronic inflammatory disease of the airway that is characterized by cellular infiltration and activation, during which eosinophils (Eos) are the main effector cells. Many studies suggest that the imbalance between Thl and Th2 lymphocytes in quantity, activity and function, as well as overexpression of adhesion molecules, such as intercellular adhesion molecule 1, play critical roles in the courses of Eos differentiation, proliferation, adhesion and migration to the airway and activation. By far,whether the bronchodilatory effect of alpha-Terpineol is associated with suppressing airway inflammation is still a mystery.Objective: To evaluate the effects of alpha-Terpineol isolated from Folium Artemisiae Argyi on airway inflammation and blood Th1/Th2 balance in a mouse model of asthma.Methods: 1 Bronchodilatory effect was investigated with bronchospasm induced by histamine aerosol in guinea pigs, antitussive and expectorant effects were studied with citric acid-induced cough in guinea pigs and excretion of phenol red in the airway of mice.2 Thirty C57BL/6 mice were at random divided into control, model and alpha-Terpineol groups, with 10 mice in each group. The mice in the model and alpha-Terpineol groups were sensitized and challenged by ovalbumin (OVA). The total leucocytes and Eos in bronchial alveolar lavage fluid (BALF) were counted, Thl/Th2 lymphocytes ratios in peripheral blood were analysed by three color flow cytometry method and the change of pulmonary pathology were detected in three groups.3 Sixty guinea pigs were at random divided into control, model, dexamethasone, alpha-Terpineol low-dose, middle-dose and high-dose groups, with 10 mice in each group. An asthmatic guinea pig model was established by OVA sensitization and challenge. The levels of plasma sICAM-1 in six groups were performed respectively by enzyme-linkedimmunosorbentassay (ELISA).Results: 1 Alpha-Terpineol (0.11g/kg, 0.54g/kg, 1.08g/kg) protected guinea pigs from histamine-induced bronchospasm and citric acid-induced cough (p<0.05-0.01).2 Alpha-Terpineol (0.18g/kg, 0.88g/kg, 1.75g/kg) increased the excretion of phenol red in the airway of mice (p<0.01).3 The total leukocytes and Eos increased obviously in BALF after OVA challenged compared with control group (p<0.01). Alpha-Terpineol (0.88g/kg) decreased the total leukocytes in BALF of asthmatic mice and resulted in a 81.04% reduction in Eos compared with model group (p<0.01).4 In control mice, there are no Eos accumulation around airways and vessels, but in model mice, there are large amount of inflammatory cells and Eos around airways and vessels. In alpha-Terpineol-administered mice, there are still a lot of inflammatory cells, mainly macrophages and lymphocytes around airways and vessels, however Eos counts decreased significantly compared with model mice.5 Blood Th2/Thl lymphocytes ratio in the model group was higher than that in the control group (p<0.01); After the administration of alpha-Terpineol (0.88g/kg), the blood Th2/Thl lymphocytes ratio decreased compared with the model group (p<0.01).6 The level of plasma sICAM-1 in the control group was lowest in the sixgroups, while the level in the model group was the highest, with significant difference between the two groups (p<0.01); Alpha-Terpineol (0.11g/kg, 0.54g/kg, 1.08g/kg) lowered the levels of plasma sICAM-1 in the asthmatic guinea pigs (p<0.01).Conclusion: 1 Alpha-Terpineol isolated from Folium Artemisiae Argyi had a certain pharmacological effects on bronchodilatation, anti...