Dynamic Analysis Of Mouse NK Cell Subsets In Eosinophilic Asthma And Establishment Of Mouse Models Of Different Asthma Subtypes

Objective:The role of NK cells in asthma is not clear. Murine NK cells can be divided into four subsets according to the surface density of CD11b and CD27. To our knowledge, no reports have been published about the phenotype changes of these subtypes in asthma. Beside this, asthma has been divided into different subtypes according to the cell characteristics in the sputum of patients in recent years. The purpose of this article is:(1) To speculate the role of NK cells in asthma after observing the dynamic changes of NK cell subsets in the lung of mouse and detecting the levels of the cells activation and secretion of cytokines in the pathological process in the mouse model of eosinophilic asthma.(2) To establish several types of mouse models of asthma to mimic different subtypes of asthma patients which could offer some support for studying the pathogenesis of asthma.Methods:Established the mouse model of eosinophilic asthma with OVA and on this basis, to establish the mouse models of neutrophilic and mix granulocytic asthma treated with different dose of LPS in different time. The numbers of different cell types in the BALF were counted under microscope following Wright-Giemsa staining. The degrees of inflammation in lungs were determined after H&E staining. The degrees of secretion of bronchial mucus were determined after PAS staining. The levels of Thl,Th2and Th17cytokines in BALF and levels of IgE and OVA-IgE in the serum were detected by ELISA. The FACS method were used for analyzing the percentages, activation and levels of secretion of cytokines of NK cells.Results:(1) In the process of eosinophilic asthma, the percentage of NK cells in lymphocytes decreased, however, more NK cells could be obseverd. The activation of NK cells enhanced and could produce both more Thl and Th2cytokines in asthma. The percentages of CDllblowCD27low and CDllblowCD27high NK subsets increased and CDllbhighCD27highand CDllbhighCD27lowNK subsets decreased. Each subsets could produce both Thl and Th2cytokines but the main products were secreted by CD11blowCD27low NK subsets.(2) The percentages and numbers of eosinophils and the levels of Th2cytokines in BALF increased in the eosinophilic asthma. The percentage and numbers of neutrophils and the levels of Thl and Th17cytokines in BALF increased in the neutrophilic asthma. The percentage and numbers of eosinophils and neutrophils and the levels of Thl, Th2and Th17cytokines in BALF increased in the mixed granulocytic asthma. Different degrees of lung inflammation and bronchus mucus secretion could be detected in different mouse models of asthma. The levels of IgE and OVA-IgE in the serum were increased in different degrees in different mouse models of asthma. Treatment of dexamethasone were effective on eosinophilic asthma rather than neutrophilic asthma or mix granulocytic asthma after assessing the changes of the percentages and numbers of cells in the BALF, the degrees of lung inflammation and mucus secretion in the bronchus, the levels of cytokines in the BALF and IgE and OVA-IgE in the serum of mice.Conclusion:1. Although NK cells is not the major lymphocytes participated in eosinophilic asthma, it may play a role in asthma for increasing numbers and activation and produce more cytokines.2. CD11blowCD27lowNK cells may be the major subsets of NK cells when paticipate in the process of asthma.3. The mouse models of asthma were established successfully which could reflect the pathological characteristics in asthma patients of different subtypes, which facilitate the further study in the pathogenesis of asthma by which could offer more targeted treatments of asthma.