ABSTRACT
OBJECTIVE@#To investigate the effects of combined infusion of mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) on lung injury after hematopoietic stem cell transplantation (HSCT).@*METHODS@#The experiment was divided into normal control group, irradiation group, bone marrow cell transplantation group (BMT group), BMT+EPC group, BMT+MSC group and BMT+EPC+MSC group. The model of HSCT was established, on the 30th day after transplantation, the mice were sacrificed. Then lung tissue was taken for testing. The mRNA expression levels of VEGF, IL-18, IL-12b were detected by RT-PCR, and protein expression level of NLRP3 was detected by Western blot. The expression of MPO and CD146 was observed by immunohistochemistry assay.@*RESULTS@#The expression level of VEGF gene in BMT+EPC+MSC group was significantly higher than that in other groups (P＜0.01). The expression level of IL-18 and IL-12b gene was the highest in BMT group and the lowest in BMT+EPC+MSC group, and the difference was statistically significant (P＜0.05). HSCT could increase the expression of NLRP3 protein, and the BMT+EPC+MSC could significantly reduce the level of NLRP3 protein in lung cells, tending to normal. Compared with normal tissues, the BMT+EPC+MSC could improve the lung tissue structure more effectively, the expression of MPO positive cells was lower, and the expression of VEGF positive cells was higher.@*CONCLUSIONS@#The combined infusion of MSC and EPC can promote capillary regeneration, alleviate inflammation and promote lung repair after HSCT, which is superior to single EPC or MSC infusion.