The Effects Of Chaipu Decoction On Expressions Of IL-17 And HDAC2 In Mice Of Steroid-resistant Asthma

Objective: To observe the effects of Chaipu Decoction on expressions of IL-17 and HDAC2 in mice of steroid-resistant asthma.Methods: According to the principle of randomization,the 30 healthy female Balb/c mice(weighing 20 ± 2)g were split into 5 groups(n=6 per group): normal group,steroid-resistant asthma group,dexamethasone group,Chaipu Decoction group and Chaipu Decoction+dexamethasone group.Except for the normal group,all the other groups were given OVA mixture 0.1ml/only(Albumin+aluminum hydroxide,OVA+AL(OH)3)sensitization,intranasal instillation of LPS 10?g(20?l)and 1%OVA multiple aerosol stimulation to produce steroidresistant asthma model,while Chaipu Decoction group and Chaipu Decoction+dexamethasone group were given Chaipu Decoction(1.5g/kg)by intragastric administration one day and an hour before each atomization.Dexamethasone group and Chaipu Decoction+ dexamethasone group were given dexamethasone(3mg/kg)by intraperitoneal injection half an hour before each atomization.Normal group was treated with the same amount of saline.Mice were sacrificed 24 hours after the last aerosolization.HE staining and pathology image analysis were performed on lung tissues.Immunohistochemistry was used to detect the levels of IL-17 and HDAC2 protein in lung tissues.We used qRT-PCR to detect the expressions of IL-17 mRNA and HDAC2 mRNA in lung tissues.PAS staining was used to observe the hyperplasia of goblet cells.Results: 1.HE staining showed that there were no airway inflammatory changes in the lung tissues of normal mice.The bronchia lumen was intact and no wall thickening;In steroid-resistant asthma mice,there were thick bronchial walls,epithelial hyperplasia,luminal stenosis,shedded cilia and a large number of inflammatory cells;Compared with the steroid-resistant asthma group,the bronchial wall thickness and inflammatory cells were lesser in the dexamethasone group and Chaipu Decoction group.It was found that the bronchial lesions were decreased significantly in the Chaipu Decoction+dexamethasone group.2.Immunohistochemistry showed that IL-17 protein expression was highest in the steroid-resistant asthma group(P<0.05).The expressions of IL-17 protein in the dexamethasone group and Chaipu Decoction group were lower than that in the steroid-resistant asthma group(P<0.05).What's more,the expression of IL-17 in the Chaipu Decoction+dexamethasone group were further reduced,and the heterogeneity compared with the dexamethasone group was significant(P<0.05);The lowest expression of HDAC2 protein were found in the steroid-resistant asthma group(P<0.05).HDAC2 protein expressions in the dexamethasone group and Chaipu Decoction group were higher than that in the steroid-resistant asthma group(P<0.05).Furthermore,the increase of HDAC2 in the Chaipu Decoction+dexamethasone group was more obvious,which was significantly different from that of the dexamethasone group(P<0.05).3.qRT-PCR showed the relative expression of IL-17 mRNA was highest in the steroid-resistant asthma group(P<0.05).Compared with steroid-resistant asthma group,IL-17 mRNA expressions decreased in the dexamethasone group and Chaipu Decoction group,and the distinction was significant(P<0.05).However,there was no significant difference between the dexamethasone group and Chaipu Decoction group(P>0.05).The relative expression of IL-17 mRNA in the Chaipu Decoction+dexamethasone group was lower than that in the dexamethasone group,and the distinguish was significant(P<0.05).HDAC2 mRNA relative expression in the steroid-resistant asthma group decreased significantly compared with the normal group(P<0.05).Compared with steroid-resistant asthma group,HDAC2 expressions in the dexamethasone group and Chaipu Decoction group increased(P<0.05).Furthermore,the HDAC2 mRNA expression in the Chaipu Decoction+dexamethasone group was higher than that in the dexamethasone group(P<0.05).4.PAS stain revealed the normal group without goblet cell hyperplasia.The goblet cells of steroid-resistant asthma group proliferated significantly compared with the normal group(P<0.05).In the dexamethasone group and Chaipu Decoction group,the goblet cells were less than that in the steroid-resistant asthma group(P<0.05).And the reduction of Chaipu Decoction+dexamethasone group was more obvious than that of the dexamethasone group(P<0.05).Conclusions: Chaipu Decoction can improve the sensitivity to glucocorticoid in steroid-resistant asthmatic mice,which the mechanism may be related to inhibition of IL-17 expression and up-regulation of HDAC2 expression.