Inhibitory Effect Of Icaritin On Ovalbumin-induced Airway Inflammation In A Murine Model

Objective: In this study,the asthma mice model was established by ovalbumin(OVA)induced airway inflammation,and then different doses of Icaritin were used for intervention to explore the potential inhibitory effect of Icaritin in asthma airway inflammation,finally hoping to provide a newly and cost-effectively potential drug for asthma treatment.Methods: 25 female C57BL/10 J mice were randomly divided into 5 groups(control group,model group(OVA),OVA+ dexamethasone group,OVA+ICT low-dose group(40 mg/kg),OVA+ICT high-dose group(80 mg/kg)).The airway inflammation model was established by intraperitoneal injection of sensitizing solution and inhalation of 1% ovalbumin.The total number of leukocytes and percentage of eosinophils in BALF of each group were counted.The inhibition effect of Icaritin on ovalbumin-induced lung tissues inflammatory infiltration was observed by Hematoxylin and eosin(H&E)staining.And periodic acid-schiff(PAS)staining was used to observe the airway goblet cell hyperplasia with mucus accumulation in ovalbumin-induced asthmatic mice with or without Icaritin treatment.Enzyme-linked immunosorbent assay(ELISA)was used to detect the effect of Icaritin on the expression of Th1/Th2 related cytokines IL-5,IL-13 and IFN-γ in serum.The regulatory effect of Icaritin on the expression of Th1/Th2 transcription factor(T-bet/GATA-3)in lung tissues in each group was detected by reverse transcription-polymerase chain reaction(RT-PCR),western blot and immunohistochemistry.Results:(1)The leukocyte counting and Giemsa staining of mice alveolar lavage fluid showed that Icaritin reduced the ovalbumin-induced eosinophils and inflammatory cells.H&E staining of mice lung tissues that in Icaritin treatment group,the degree of inflammatory pathological grade,the degree of congestion of bronchial mucosa and infiltration of inflammatory cells in lung tissues were lower compared with asthma group.PAS staining showed the positive cells was fewer in Icaritin group than that of asthma group,showed that Icaritin reduced airway goblet cells hyperplasia with mucus accumulation.(2)The results of ELISA showed that the level of IFN-γ was higher while the levels of IL-5 and IL-13 were lower in Icaritin group compared with asthma group and dexamethasone group.(3)The RT-PCR results showed that the lung tissues T-bet m RNA increased,while the expression of GATA-3 m RNA decreased in Icaritin group compared with OVA group.The results of Western blot and immunohistochemistry showed that the protein of T-bet increased whilethe protein of GATA-3 decreased in the lung tissues in Icaritin group compared with OVA group.Conclusions:(1)Icaritin inhibits the airway inflammation in ovalbumin-induced asthma mice.(2)Icaritin regulates Th1/Th2 related cytokines expression in serum of asthma mice.(3)Icaritin rebalances the expression of Th1/Th2 transcription factors(T-bet/GATA-3)in lung tissues in ovalbumin-induced asthma mice.