Effect of bacteria lysates and 1, 25 - dihydroxy vitamin D3 on airway inflammation in asthmatic mice models

Abstract

Objective To discuss the effects of bacteria lysates(OM-85BV), 1, 25 - dihydroxy vitamin D3 [1, 25-(OH)2-VitD3], two immune regulators on airway inflammation in asthmatic mice models, and its pathways of action on airway inflammation were discussed. Methods Forty male BALB/c mice graded 4-6 weeks were randomly divided into 5 groups.Group A: control group; group B: asthmatic model group; group C: 1, 25-(OH)2-VitD3 group; group D: OM-85BV group; group E: combination group.On days 0 to 14, mice in C, D and E groups were given 1, 25-(OH)2-VitD3, OM-85BV and 1, 25-(OH)2-VitD3+ OM-85BV, and mice in A, B groups were given 9 g/L saline instead.On days 15, 22 and 29, mice in B, C, D, E groups were intraperitoneally with injection of ovalbumin(OVA)- aluminum hydroxide [Al(OH)3]. Group A were given 9 g/L saline instead.On days 36 to 40, mice of B, C, D, E groups were given an aerosol challenge of 10 g/L OVA for 0.5 h once a day.Mice in the control group were given the same amount of 9 g/L saline.Animals were sacrificed 24 hours after the final inhalational challenge, and for the recovered bronchoalveolar lavage fluid(BALF) of the left lung was used for differential inflammatory cell counts and for detecting the level of inflammatory cytokine interleukin-17(IL-17). Right lung samples were used for pathological investigation and detecting the expression of the IL-17 mRNA and RORγt mRNA by real time-PCR. Results Compared with the control group, the asthma models expressed more serious expression in bronchospasm contraction, hyperplasia disorders of bronchial epithelial cells, infiltration of inflammatory cells in lung, and so on.Compared with the control group, the total number of inflammatory cells counts[(104.04±5.51) 107/L vs (22.79±1.91) 107/L] and eosinophils proportion[(37.63±3.64)% vs (2.37±1.55)%] in BALF in group B were significantly increased (all P<0.05), the levels of IL-17 [(85.13±5.77) 103 pg/L vs (47.44±4.57) 103 pg/L] in BALF were significantly higher(P<0.05), the relative expressions of IL-17 mRNA(13.68±1.59 vs 1.00±0.00) and RORγt mRNA (4.53±0.51 vs 1.00±0.00)in lung were higher, which had a statistical significance(all P<0.05). The situations of group C, D, E were obviously improved compared with group B, and those of group D were improved remarkably. Conclusions Oral OM-85BV and 1, 25-(OH)2-VitD3 intervention could relieve the airway inflammation of asthmatic mice models, and its effect can be remarkable by oral OM-85BV.The two immune regulators could relieve the degree of airway inflammation on asthmatic mice models by reducing the expression of Th17 cells differentiation.Therefore the two immune regulators could be the choices for preventing the happening and the development of the asthmatic airway inflammation. Key words: Asthma; Bacteria lysates; 1, 25-dihydroxy vitamin D3; Th17 cell