Effects Of Inhaled Inactivated-mycobacterium Phlei On Expression Of IL-17F In Asthma Mice

Objective To investigate the effects of interleukin-17F （IL-17F）expression on airway inflammation and airway hyperresponsiveness（AHR）in asthma mice model with treatment of inhaled Inactivated-MycobacteriumPhlei.Methods24male BALB/c mice were divided into3groups (8mice pergroup) according to a random number table: control group, model group, andtreatment group. Modeling asthma mice sensitized with Ovalbumin (OVA).Mice in model group and treatment group were injected intraperitoneally with0.2ml suspension mixture of25μg OVA and1mg aluminium hydroxides forsensitization on the1st day, the8thday and15thday. From22ndto28th, the micesensitizated with OVA were respectively put into an airtight atomizing box andinhaled2%atomizing OVA PBS suspension30min once a day. Treatment groupcontinued being inhaled inactivated-mycobacterium phlei30min once a dayfrom29thto34th, while control group were intraperitoneally injected andinhaled with PBS instead of OVA.Observed mice behaviours and active changesduring atomization process, each group was immediately performed invasiveairway resistance test at the end of the last inhalation; collecting mice broncho alveolar lavage fluid （BALF） for counting inflammatory cells and theclassification proportion; observing the airway structure and pathologicalchanges of mice lung tissue that treated with HE staining and PAS stainingunder the light microscope and performing pathological semi-quantitative scoreto estimate the severity of airway inflammation; enzyme-linked immuno sorbentassay(ELISA) is applied to testing IL-17F concentration in serum andbroncho alveolar lavage fluid(BALF); determining IL-17F expression changesin asthma mice lung tissue with reverse transcription-polymerase chain reaction(RT-PCR) test; SPSS16.0was used for statistical analysis.Results Typical animal asthmatic attack symptom appeared during theprocess of OVA atomization and excitation in sensitized mice. Airway resistanceof model group is significantly higher (P<0.01) than that in control group andtreatment group; total cellular score [(75.93±3.03)×104/ml], eosinophilspercentage [(19.02±2.01)%] and neutrophilics granulocyte percentage[(17.01±0.91)%] in BALF also distinctly rised(P<0.01). Airway resistancedeclined (P<0.01) and airway total cellular score [(59.41±2.73)×104/ml],eosinophils percentage [(13.37±1.88)%] and neutrophilic granulocytepercentage [(13.87±0.93)%] in treatment group all reduced to varying degreesafter the treatment of inhaled inactivated-mycobacterium phlei. Pathologicchanges in asthma mice lung tissue were airway mucosa incrassation, goblet cellhyperplasia, permutation disorder, mass mucus secretion, lumen narrowness,tissue edemas around airway and blood vessel, and obvious inflammatory cellinvasiveness, while the above pathologic changes were improved in treatmentgroup. IL-17F concentrations in BALF are all higher than those in serum;IL-17F concentration [(183.04±14.03) pg/ml] in BALF of model group issignificantly higher than that in control group [(50.44±4.55) pg/ml] and treatment group [(114.36±7.93) pg/ml], the difference is statistical significance(P<0.01); IL-17F concentration in BALF of treatment group is lower comparedwith that in model group, but is still higher than that in control group， thedifference is statistical significance (P<0.01). IL-17F concentrations in serum ofmodel group [(9.20±2.41) pg/ml] and treatment group [(6.36±1.15) pg/ml] areboth higher than that in control group [(3.29±0.77) pg/ml], and the difference isstatistical significance (P<0.01).IL-17F concentration in serum of treatmentgroup is lower compared with that in model group with no significant difference(P>0.05). IL-17F mRNA relative expression in mice lung tissue of model groupis significantly higher than that in control group and treatment group (P<0.01).IL-17F mRNA expression is not significantly different (P>0.05) in mice lungtissue of asthma group after the treatment of inhaled inactivated-mycobacteriumphlei compared with that in control group. The gene expression of IL-17F inlung tissue has a positive correlation between both eosinophils percentage（r=0.710，p<0.01） and neutrophils percentage（r=0.818，p<0.01）in BALF.There is a positive correlation between IL-17F mRNA expression in lung tissueand airway resistances that were determined after stimulations of different Mchconcentrations（6.25mg/ml、12.5mg/ml、25mg/ml、50mg/ml）, and the resultsof correlation analysis are the following: r=0.751，p<0.01；r=0.695，p<0.01；r=0.897，p<0.01；r=0.934，p<0.01.Conclusion Airway inflammation and airway hyperreactivity in asthmamice model is connected with IL-17F high expression. Aerosol inhalationinactivated-mycobacterium phlei can reduce airway inflammation and IL-17Fexpression in astnma mice model and significantly improve airwayhyperreactivity, thus controling asthmatic attack.