Role of Low Dosage Arsenic Trioxide on Pulmonary Dendritic Cells in Asthmatic Mice

Objective: To investigate the distribution and recruitment of pulm onary dendritic cells (DCs) and the influence of low dosage arsenic trioxide (As 2O 3) on them in the airway of asthmatic mice. Methods: Thirty BALB/c mice were randomly divided into 3 groups: the control group, the asthmat ic group and the As 2O 3 treated group. The mice asthmatic model was induced v ia sensitizing with peritoneal injection of ovalbumin (OVA) for two times and th en provocated with aerosol inhalation of OVA for a week. The treated group was p eritoneally injected with 0.2 ml solution of As 2O 3 (4mg/kg) 0.5h after each provocation. The immunohistochemistry and computerised image analysis were appli ed to detect quantitatively the DCs in the lung and airway of mice. Resul ts: All intraepithelial nonlymphoid dendritic cells 145 (NLDC 145) throughout the respiratory tree in the mice of the control group formed a netwo rk with the density of DCs varying from (575±54) cells/mm 2 epithelial surface in the large airway, to (68±12) cells/mm 2 epithelial surface in the small ai rway. The distribution of airway NLDC 145 + in the asthmatic group was simil ar to that in the control group, but its density was significantly upregulated ( P <0.01). The distribution of airway NLDC 145 in the treated group was sim ilar to that in the asthmatic group, only its density was significantly downregu lated ( P <0.01). Conclusion: There is an integral network of N LDC 145 + throughout the respiratory tree. To downregulate the density but n ot change the distribution of pulmonary DCs could be an important therapeutic me chanism of low dosage As 2O 3 in treating asthma.