The Mechanism Of Exosome From HucMSC Ameliorate Inflammatory Bowel Disease Through Regulate The Expression Of IL-7 In Macrophage

Objective: We established the model of exosomes released from human umbilical cord mesenchymal stem cells(hucMSCs)on the treatment of dextran sulfate sodium-(DSS-)induced inflammatory bowel disease(IBD)to identify the function of macrophage regulated by hucMSC-Ex on treatment of IBD and to explore the effect of hucMSC-Ex on the treatment of IBD by downregulate the expression of IL-7 in macrophage.Methods: To establish the model of hucMSC-Ex allivating the model of DSS-induced IBD in BALB/c mice,male BALB/c mice were randomly divided into three groups: control group(normal),DSS-induce IBD group(IBD)and exosomes-treated IBD group(IBD+Ex).The weight of the mice were measured,the changes in the feces of the mice were observed,and the pathological analysis was used to evaluate the severity of IBD every day.The mice were sacrificed and the tissues of colon and spleen were collected for further studies on day 11.The morphology structure of the tissues in the spleen and colon were observed and the total RNA and protein were extracted.The mRNA expression of TNF-α,IL-1β,IL-6 and IL-10 were detected by QRT-PCR.The severity of colon mucosa and spleen tissues were analyzed by H&E staining.All of results were used to evaluate the effects of hucMSC-Ex on the treatment of IBD.The expression of iNOS and CD206 in the colon tissues and spleen tissues of three groups were detected by QRT-PCR and immunohistochemistry.To analyze the infiltration degree of macrophages and the secreted cytokine in hucMSC-Ex repaired mice of DSS-induced IBD.The expression of IL-7 in different groups were detected by western-blot,immuno-histochemistry and QRT-PCR.In addition,macrophages were incubated with hucMSC-Ex for 48 h and harvested for further studies.Macrophages from different groups were collected and the expression of IL-7 and inflammatory cytokines were detected by western-blot and QRT-PCR.The function of macrophage in the DSS-induced IBD mice repaired by hucMSC-Ex was analyzed.Resules: All the mice were sacrificed on day 11.Compared with the IBD group,hucMSC-Ex significantly inhibited the weight loss in IBD mice.The results of QRT-PCR showed that the expression of pro-inflammatory cytokines such as TNF-,IL-1β,and IL-6 increased in IBD mice while decreased in those of hucMSC-Ex-treated mice.In contrast,the expression of anti-inflammatory cytokine IL-10 was increased in the colon tissues of hucMSC-Ex-treated IBD mice compared with that in IBD mice.The results of western-blot and QRT-PCR showed that the expression of IL-7 was significantly decreased in that of hucMSC-Ex-treated mice.HucMSC-Ex significantly downregulated the IL-7 expression in the macrophages incubated with hucMSC-Ex.Conclusions: The results have shown that hucMSC-Ex have therapeutic effects on the mice of DSS-induced IBD.The possible mechanism of hucMSC-Ex relieving the IBD is that hucMSC-Ex may exert their function through downregulating the expression of IL-7 in macrophages.This study provides a new theoretical theroy and experimental basis for hucMSC-Ex in the treatment of IBD,which has an important value of clinical application.