Effects Of Inhalation With Aqueous Extract Of Ephedra On The Airway Inflammation In Asthmatic Mice

Objective:To study the effects of aqueous extract of ephedra on the the airway inflammation and the expression and activation of interleukin-13(IL-13), eosinophil chemotactic factor(Eotaxin) in airway of asthmatic mouse model through aerosol inhalation, and to explore the possible mechanism of ephedra in the therapy of asthma. Methods:(1) Ephedra, soaked in water for 30min, was decocted for 1 hour and concerntrated (1g/ml, calculated by containing ephedra), stored in 4℃refrigerator. (2)24 BALB/c female mice(5 to 6 weeks old,16 to 20g weight) were randomly divided into three groups:control group(group A), asthma group(group B), ephedra group(group C). Each group had 8 mice. The asthmatic model were established by ovalbumin in group B and group C. Mice were immunized on days 0 and 7 by intraperitoneal injection per day with 0.2ml of antigen solution which contains 100μg OVA and 1mg Al(OH)3. From day 14 the mice were challenged by drip 40μl of 2% OVA solution into nose per day on 7 consecutive days. Mice in group C, 1h before instillation at every time, were aerosolized with 50ml aqueous extract of ephedra for 30min twice on 9 consecutive days. Equal NS was used for intraperitoneal injection, sensitization and inhalation instead of antigen solution in group A, while equal NS was used for inhalation in Group B. On days 21and 23, mice were killed to get the sample of bronchoalveolar lavage fluid(BALF) and the pulmonary tissues. (3)The number of WBC and EOS in BALF were counted. Lung tissues were sliced and stained with hematoxylin and eosin. The pathological changes in bronchial and lung tissues were observed by electron microscopy. The expression of IL-13 and Eotaxin in bronchial and lung tissues was measured by immunohistochemi-stry(SP) method. The concentration of IL-13 and Eotaxin was detected by double-antibody sandwich enzyme-linked immunosorbent assay(ELISA). The above parameters in all groups were analyzed by SPSS17.0. Results:(1)The number of WBC and EOS in group B was significantly higher than that in group A(P<0.05); While the number of WBC and EOS in group C was significantly lower(P<0.05), but still higher than that in group A(P<0.05). (2) Conventional pathological studies showed that:Group A:There were completed airway epithelial, thin bronchus and bronchioles smooth muscle, regulation lumens, no secretion, low mucosal folds, normal alveolar septum, no significant inflammatory cell infiltration around. Group B:There were incomplete epitheliums, bronchial stenoses, significant hyperplasia of basement membrane, mucus plug, airway epithelial hyperplasia, smooth muscle and alveolar septum thickening, obvious inflammatory cell infiltrated around. Group C:There were less inflammatory cell infiltrated around bronchus and pulmonary alveoli, thinner alveolar septum, larger alveolar space, bronchial wall thickening and bronchial stenoses were improved. (3)Immunohistochemistry showed that:The number of positive cells in group B was significantly increased compared with group A(P<0.05); Compared with group B, the number of positive cells in group C was significantly decreased(P<0.05). (4)ELISA illustrated:The concentration of IL-13 and Eotaxin in group B was significantly higher than that in group A and group C(P<0.05). The concentration of IL-13 and Eotaxin in group C was decreased compared with group B(P<0.05). (5)The concentration of IL-13 was positively correlated with the number of EOS(r=0.746,P<0.05; r=0.729, P<0.05). There was a positive correlation between the expression of Eotaxin and the number of EOS(r=0.712, P<0.05; r=0.734, P<0.05). The concentration of IL-13 and Eotaxin was positively correlated. The concentration of IL-13 and Eotaxin was significantly increased in group B(r=0.803, P<0.05), both obviously decreased in group C(r=0.761, P<0.05). Conclusion:(1)The expression of IL-13 and Eotaxin at protein level is up-regulated in airway of allergic asthmatic mice. (2)The inhalation of aqueous extract of ephedra can relieve airway inflammation in asthmatic mice. (3)The anti-inflammation mechanism of ephedra is probably related to inhibiting the expression of IL-13 and Eotaxin in airway of asthmatic mice.