Study On The Regulation Effect Of Astragaloside Ⅳ On Th17/Treg Cells In Asthmatic Mice

Bronchial asthma is a kind of chronic airway inflammatory disease,which is involved in many kinds of cells and its cytokines.Although there have been many studies on the pathogenesis of asthma,the pathogenesis is very complicated,so it is not clear yet.Studies have shown that T lymphocytes play an important role in airway inflammation of asthma.Previous studies have shown that the imbalance of Th1/Th2 cells is the main mechanism of the development of asthma,but with the deepening of the study,It was found that the imbalance of Th1/Th2 cells could not completely explain the occurrence of asthma.In recent years,studies has been found that the imbalance between Th17/Treg cells can also lead to the occurrence of asthma.The cytokine IL-17 of Th17 cells causes inflammatory cells to gather in the airway of asthma,while IL-10 secreted by Treg cells inhibits the immune response.However,the role of Th17/Treg cells in the pathogenesis of asthma is unclear.Currently,inhaled corticosteroids(ICS)is the first choice to control the clinical symptoms of asthma.However,whether long-term use of corticosteroids will affect the growth and development of children.The side effects of traditional Chinese medicine on asthma are less,and the curative effect is certain.It has been proved that Astragalus can regulate the balance of Th1/Th2 cells in the asthma model.Astragalus membranaceus has immunomodulatory and anti-inflammatory effects on the body.Astragaloside Ⅳ(AS-Ⅳ)is the main active component of Astragaloside.At present,there are few studies on whether Astragaloside Ⅳ can regulate the balance of Th17/Treg cells.In this study,we will explore the relationship between Th17/Treg imbalance and the occurrence and development of asthma.And the effect of Astragaloside Ⅳ on Th17/Treg balance in asthmatic mice.32female specific-free(SPF)BALB/c mice aged four weeks,weighing(13 ±1)g,,the mice were randomly divided into normal conctrol group,asthma model group,Astragaloside Ⅳ treatment group,Budesonide treatment group with 8 mice in each group after 3 days of adaptive feeding.asthma model group,Budesonide treatment group and Astragaloside Ⅳ treatment group,each mouse was on days 1,8,15 of the experiment,intraperitoneal injection of ovalbumin(OVA)sensitized 0.2m L liquid(containing twelve water 1mg;OVA100 μg;Phosphate Buffered,Saline(PBS)).The mice in normal conctrol group were sensitized by PBS.asthma model group,Budesonide treatment group and Astragaloside Ⅳ treatment group were placed in self-made atomization box daily from the 22 nd day of experiment,excited by atomization of 5%OVA solution,and the normal conctrol group was inhaled with PBS atomization once a day for 30 minutes for 14 days.half an hour before the nebulization challenge,for Astragaloside Ⅳ treatment group,Astragaloside-carboxymethylcellulose suspension liquid was administererd via the gastrointestinal tract.In Budesonide treatment group,budesonide mixture was given(1 mg / 2 m L budesonide suspension,2 m L normal saline).normal conctrol group,asthma model group and Astragaloside Ⅳ treatment group were given the same amount of normal saline atomization at the same time;normal conctrol group,asthma model group and Astragalus Ⅳ group were given the same amount of carboxymethylcellulose sodium(CMC)solution by intragastric perfusion.The mice were given OVA atomization inhalation and astragaloside Ⅳ intragastric administration for the last time.After 24 hours of fasting,anesthetized mice were injected intraperitoneally with 1% pentobarbital.After the neck was put to death,the left lung was perfused with PBS solution and the bronchoalveolar lavage fluid(BALF)was slowly redrawn.The BALF was collected.BALFwas centrifuged at 1500 r / min,10 min,4 and stored at ℃-80 ℃.Enzyme linked immunosorbent assay(Elisa)was used to detect the expression of IL-17 、IL-10 cytokines in BALF.Some of the right lung tissues were stained with HE、AB-PAS,and the expression of IL-17 IL-10 cytokines in BALF was detected by Elisa.Lung pathological changes were observed in each group of mice.Partial lung tissues were extracted and RNA integrity was detected by electrophoretic assay.Real time quantitative polymerase chain reactionation(RT-PCR)was used to detect the expression of Foxp3 m RNA and RORγt m RNA in lung tissues.By OVA sensitization and excitation of asthmatic mice during excitation showed varying degrees of shortness of breath,wheezing,irritability,abdominal cramps,scratching nose positive behavior,and Astragaloside Ⅳ treatment group and Budesonide treatment group symptoms alleviated,the normal conctrol group had no obvious change.The lung tissues of asthmatic mice were observed under light microscope,and eosinophils,neutrophils and other inflammatory cells increased,goblet cells proliferated,and airway lumen narrowed.Compared with the normal conctrol group,the level is increased the expression of IL-17 in BALF of asthma model group(P<0.05),and the expression level of IL-10 decreased(P<0.05),the expression of RORγtm RNA in lung tissue was increased(P < 0.05),and the level of Foxp3 m RNA was decreased(P < 0.05).The expression level of IL-17 in BALF of Astragaloside Ⅳ treatment group and Budesonide treatment group was lower than that of asthma model group(P < 0.05),but the expression of IL-10 was increased(P < 0.05),there was no significant difference in the expression of IL-17 and IL-10 in BALF between Astragaloside Ⅳ treatment group and Budesonide treatment group.(P>0.05);the expression of RORγtm RNA in lung tissue of Astragaloside Ⅳ treatment group and Budesonide treatment group was lower than that of asthma model group(P < 0.05),but the Foxp3 m RNA expression level was increasing.(P<0.05),There was significant difference in the expression level of RORγtm RNA-Foxp3 m RNA in lung tissue between Astragaloside Ⅳ treatment group and Budesonide treatment group.(P<0.05)The results of this study show that the imbalance of Th17/Treg cells is involved in airway inflammation in asthma.Astragaloside Ⅳ can increase the expression level of Treg cells by downregulating the secretion of Th17 cells,maintain Th17/Treg cell balance,reduce inflammatory cell aggregation in asthmatic airway and relieve asthma symptoms.