Effects of eosinophils deletion on sPLA2-X in bronchial asthma model mice

AIM To investigate the association between soluble phospholipase A2-X（sPLA2-X） and eosinophils in bronchial asthma， and to provide new insight and strategies for the treatment of bronchial asthma. METHODS Female Babl/c mice （n=48） of SPF grade and 6~8 weeks old were divided into 4 groups （with 12 in each group： healthy control group，asthma control group， eosinophil deletion group， and asthma /eosinophil deletion isotype control group）. The mouse model of bronchial asthma was constructed. The mice in healthy control group were intraperitoneally injected with saline on days 0， 7， and 14. The mice in other groups were intraperitoneally injected with 50 μg OVA and 2 mg aluminum hydroxide gel（soluble in 200 μL saline.On the 21st d and 26 th d， eosinophil deletion antibody （anti-CCR3） and isotype control were intraperitoneally injected and intranasally respectively， and then the lungs function test was conducted within 48 h after the end of nebulization.Half of the mice in each group were subjected to whole lung lavage， the remaining half were used for lung tissue section with HE staining， the whole blood was used to measure serum IgE， the supernatant of broncho alveolar lavage fluid （BALF） was used to measure cytokines， and total number of cells in the bronchoalveolar lavage fluid was analyzed for cell classification and flow cytometry. RESULTS （1）Compared with asthma control group，the airway and alveolar inflammatory responses in asthma/eosinophil deletion group was significantly alleviated.（2） Compared with asthma control group， anti-CCR3 successfully deleted eosinophils， and the percentage of eosinophils in bronchoalveolar lavage fluid in asthma/eosinophil deletion group was significantly reduced （P<0.05）.（3） The airway hyperresponsiveness in asthma/eosinophil deletion group was significantly decreased as compared with asthma control group（P<0.05）.（4） The levels of sPLA2-X in the serum and BALF was significantly reduced in asthma/eosinophil deletion group as compared with asthma control group（P<0.05）.（5）Compared with asthma control group，the levels of IL-4， IL-5， and IL-13 in the BALF of the mice in asthma/eosinophil deletion group were significantly reduced， and the serum level of IgE was also decreased （P<0.05）. CONCLUSION Eosinophils in bronchial asthma are importantly associated with sPLA2-X.