Effects Of Different Probiotics On Asthmatic Rats

Background:Bronchial asthma is one of the most common chronic lung diseases in children.the prevalence rate of asthma in children aged 13-14 years is 13.8%.The third asthma epidemic in China:in 2010,the prevalence rate of asthma in children under 14 years old in Chinese cities was 3.02%.Asthma has a certain negative impact on children’s later life and study,and increases the financial burden of the family.Therefore,early diagnosis and active treatment are of inestimable value to the society.The Hygiene hypothesis proposes that excessive cleaning of the natural environment leads to a decrease in the number of intestinal flora in children.Studies have shown that intestinal flora and their metabolites reduce the incidence of atopic diseases and maintain immune stability.Objective:The purpose of this study is to explore the effects of different probiotics on asthma,and whether the effect of mixed probiotics on asthma is better than that of single probiotics.The rat model of acute asthma was made by sensitization with ovalbumin.Lactobacillus rhamnosus,Clostridium butyricum and their mixture were given intragastrically.The behavioral changes of rats were observed,the total leukocyte count and classification ratio of bronchoalveolar lavage were counted under microscope,the contents of cytokines IL-4,INF-y and Ig-E in serum were determined by ELISA,the pathological changes of lung tissue were observed,and the effects of different probiotics on rat asthma were evaluated.Methods:Fifty wistar rats were divided into five groups:control group(group N),asthma group(group A),Lactobacillus rhamnoides group(group L),Clostridium butyricum group(group C)and mixed bacteria group(group M).All probiotics groups were given oral probiotics on days 0-28;except the control group,the other four groups were sensitized by intraperitoneal injection of ovalbumin and AL(OH)-3 on the 7th and 14th days,and OVA was stimulated by continuous aerosol inhalation on the 21st-28th day.The control group was given normal saline intragastric administration,intraperitoneal injection and aerosol inhalation at the same time.On the 28th day,the rats were killed after intragastric administration and atomization.After anesthesia,the blood was collected by apical puncture,and the serum was taken after centrifugation.The contents of cytokines IL-4,INF-y and IgE were determined.The right lung was ligated and the left lung was lavaged.The total number and classification of leukocytes were counted under microscope,and the pathological changes of lung tissue were observed by Hype staining.Results:1.Establishment of rat asthma model;2.There were no special behavioral changes in the control group,but the allergic symptoms were the most obvious in the asthma group,such as unstable gait,jumping and spasm,shortness of breath,urination and defecation in the single probiotic group,and scratching and sneezing in the mixed probiotics group;3.Pulmonary inflammatory cells:compared with the control group,the total leukocyte count of BALF in the asthma group increased most significantly,and the percentage of eosinophils and neutrophils increased.Compared with the asthma group,the total leukocyte count decreased,the percentage of macrophages increased and the eosinophil decreased in the probiotics group.Compared with the single probiotics group,the total number of leukocytes and the proportion of eosinophils and neutrophils in the mixed probiotics group were lower than those in the single probiotics group(P<0.001);4.Serum cytokines:compared with the control group,the content of serum INF-γ in the asthma group decreased significantly,while IL-4 and IgE increased significantly(P<0.001).Compared with the asthma group,all probiotics groups showed an increase in INF γ(P<0.001),IL-4(P<0.01)and IgE(P<0.05.Compared with the single probiotics group,the level of INF-y in mixed probiotics group increased,while IL-4 and IgE decreased.There was no significant difference in the contents of INF-y,IL-4 and IgE between Lactobacillus rhamnosus group and Clostridium butyricum group;5.Histopathological changes:compared with the control group,the bronchial lumen was narrowed and a large number of inflammatory cells infiltrated around the bronchi and blood vessels in the asthma group;compared with the asthma group,the degree of bronchial wall edema and inflammatory cell infiltration decreased in all probiotics groups;the alveolar wall in the mixed probiotics group was thinner than that in the single probiotics group,and the number of surrounding inflammatory cells was the least,and there was no significant difference in pathological changes between Lactobacillus rhamnoides group and Clostridium butyricum group;Conclusion:probiotics can reduce allergic airway inflammation,reduce pulmonary inflammatory cells and correct the imbalance of Th1/Th2 in rats,and the anti-allergic effect of combined probiotics is stronger than that of single probiotics.