Dynamic changes of CD34⁺ progenitor cells and eosinophils in asthmatic mice and their relationship with CCR3/eotaxin expression

Objective The dynamic changes of eosinophils, CD34⁺ progenitor cells, eotaxin and CCR3 expression in BALF, peripheral blood, bone marrow suspension of asthmatic mice were studied by asthma model. This study aims to investigate the relationship between airway eosinophil inflammation and CD34⁺ progenitor cells and CCR3/eotaxin in asthmatic mice. Methods C57BL/6 mice were used to establish asthma model with ovalbumin as antigen. The changes of eosinophils, CD34⁺ progenitor cells and eotaxin in BALF, peripheral blood and bone marrow were detected 6 hours, 12 hours, 24 hours and 48 hours after the last antigen challenge, and the expression of CCR3 on CD34⁺ progenitor cells was detected. Lung biopsy was used to observe eosinophil infiltration. Lung tissue CCR3 and eotaxin mRNA levels were detected by PCR. Results The results showed that eosinophils, CD34⁺ cells and CD34⁺/CCR3⁺ cells were increased in BALF, peripheral blood and bone marrow suspension. The eotaxin level of BALF in the model group increased significantly at 6 h compared with the control group (P<0.05), and lasted until 24 h. The level of eotaxin in peripheral blood and bone marrow suspension was not significantly different from that in the control group (all P>0.05). The expression of eotaxin mRNA and CCR3 mRNA in lung tissue of model group increased significantly at each time point compared with control group. The number of eosinophils in BALF was positively correlated with the number of eosinophils and CD34⁺/ CCR3⁺ cells in bone marrow, but not with the number of CD34⁺ cells in bone marrow. Conclusion ①The increase of eosinophils in airway of asthmatic mice is related to the up-regulation of CCR3 expression in bone marrow CD34⁺ progenitor cells. ②CCR3/eotaxin participates in the differentiation and chemotaxis of CD34⁺ progenitor cells. It is closely related to airway eosinophil infiltration in asthmatic mice.