OBJECTIVE To explore the therapeutic effect of human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)in mouse model of allergic lung inflammation.METHODS hUC-MSCs were isolated and cultured from umbilical cord of healthy neonates.The expression of MSC cell surface markers were assessed by flow cytometry in the fifth generation of hUC-MSCs.Mice were sensitized by intraperitoneal injection of ovalbumin and challenged via inhalation of aerosolized ovalbumin to establish an allergic airway inflammation model.The same dose of normal saline was used in the control group.After 14 days of nebulization,lung tissues and bronchoalveolar lavage fluid(BALF)were collected from the mice.Hematoxylin and eosin staining and Luminex multiplex assay were performed to assess the levels of allergic inflammation.Lung tissues were minced,homogenized,and digested into single-cell suspensions for cell culture.hUC-MSCs or human nasal epithelial cells were co-cultured with mouse lung cells at a ratio of 1:5 or 1:10(cell number ratio).After 18 hours,the supernatants were collected,and Luminex multiplex assay was performed to assess the expression of inflammatory cytokines interleukin-5(IL-5)and IL-6.RESULTS Cultured hUC-MSCs showed an elongated spindle-shaped morphology.The positive markers CD105,CD73,and CD90 showed positive rates of>95%respectively,while the negative markers CD45,CD34,and CD11b exhibited positive rates of<2%respectively.Compared with the controls,the allergic mice showed significant infiltration of eosinophils in the peribronchial regions of lung tissues,and increased expression levels of IL-5(P<0.01)and IL-6(P<0.05)in BALF.Compared with the control group,mouse lung cells co-cultured with hUC-MSCs significantly decreased the levels of IL-5 and IL-6 in the supernatant(both P<0.05 in 1∶5 group and 1∶10 group).CONCLUSION Co-culture with hUC-MSCs can significantly ameliorate allergic inflammation in lung tissue of mouse model,indicating the therapeutic potential of hUC-MSCs in airway allergic inflammation.