Objective  To investigate the effects of a mixed bacterial lysate (OM-85 BV) on lung function and serum IgE in asthmatic mice under acute attack, and to explore the therapeutic effect of OM-85 BV on acute attack and the application value of OM-85 BV in non-acute attack. Methods  A total of 30 SPF Kunming mice aged 4 to 6 weeks were randomly divided into 3 groups, namely a blank control group (Group A), an asthma model group (Group B), and an OM-85 BV intervention group (Group C). The mice in groups B and C were sensitized by intraperitoneal injection of ovalbumin on day 1, 8 and 15, respectively. From day 22, the asthma model was stimulated by inhalation of 5% ovalbumin every day for 30 min for 5 consecutive days. The mice in group C were treated with OM-85 BV dissolved in normal saline from day 1, and each mouse was gavaged continuously for 10 days. The intraperitoneal injection, intragastric administration and aerosol inhalation reagent of mice in group A were all replaced by normal saline, while the intragastric administration of mice in group B was replaced by normal saline. One hour after the last stimulation, the mice were anesthetized, their lung function was measured, blood was collected from the eyeballs and then they were sacrificed, and the blood was centrifuged and the serum was separated and stored. Hematoxylin and eosin staining was used for pathological examination. Serum IgE was determined by enzyme-linked immunosorbent assay. Results  Compared with group A, forced vital capacity in 0.15 second (FEV_0.15), FEV_0.15/forced vital capacity (FVC) and peak expiratory flow (PEF) of mice in group B were significantly decreased. The lung function of group C was improved compared with group B. In group B, the pathological manifestations were dysplasia and collapse of bronchial epithelium, infiltration of inflammatory cells, mainly lymphocytes and eosinophils, a small amount of mucus and shed epithelial cells in the tracheal lumen, and significant thickening of airway wall. The asthma mouse model was well established. The pathological manifestations of airway in group C were less severe than those in group B, the thickness of airway wall was reduced, and the inflammatory cells were also significantly reduced. The serum IgE concentration in groups B and C increased, and the IgE level in group C decreased significantly compared with group B. The differences were statistically significant (all P<0.05). Conclusions  Exogenous administration of OM-85 BV in asthmatic mice can effectively reduce the concentration of serum IgE, alleviate airway inflammation, reduce eosinophil infiltration, and improve the pulmonary function performance of asthmatic mice during acute attack, showing that FEV_0.15/FVC, FEV0.15 and PEF indicators are significantly improved. OM-85 BV can alleviate the symptoms of bronchial asthma in the acute attack of mice, improve the physiological function of the lung during the acute attack, inhibit airway inflammation, and have certain application value in the stable asthma control.

Citation： WU Qihe, GAO Yang, CAI Zhiping, SHI Jinghua. Effects of bacterial lysates on lung function and serum IgE in mice with acute exacerbation of asthma. Chinese Journal of Respiratory and Critical Care Medicine, 2022, 21(12): 873-877. doi: 10.7507/1671-6205.202208026 Copy