Fig 2: The interleukin (IL)-7?CD127 signaling pathway is downregulated in intestinal epithelial cells and intraepithelial lymphocytes (IELs) following ischemia/reperfusion (I/R). (A) The expression level of the IL-7 protein (green) was significantly decreased in the mid-to-distal villus region after 6 h of I/R according to immunofluorescence staining. (B) The expression levels of phosphorylated CD127 and STAT5 were both significantly downregulated after 6 h of I/R in IELs. *P<0.05, 3-4 mice/group; the results are representative of three independent experiments.

Fig 3: Bone morphogenetic protein (BMP)4 regulates the interleukin (IL)-7a/CD127 signaling pathway in intestinal epithelial cells (IECs) and intraepithelial lymphocytes (IELs). (A) Western blot analysis determined the expression of IL-7 in IEC-6 cells following treatment with BMP4 for 6 h. The IL-7 level was significantly decreased compared with that in the control group. (B) Flow cytometry, was used to detect the expression of CD127 and phosphorylated signal transducer and activator of transcription (STAT)5 proteins following treatment with BMP4 for 6 h. The levels of CD127 and phosphorylated STAT5 proteins were significantly decreased compared with those in the control group. Each experiment was repeated three times; 4-5 mice/group. *P<0.05 for control vs. treatment with BMP4 alone; **P<0.05 for control vs. the BMP4 + NOGGIN group. GAPDH, glyceraldehyde 3-phosphate dehydrogenase.

Fig 4: Inhibition of bone morphogenetic protein (BMP)4 induces the apoptosis of intraepithelial lymphocytes (IELs) that has been stimulated by interleukin (IL)-7. Flow cytometry and apoptosis markers (FITC-Annexin V and PI) were used to examine IEL apoptosis after treatment with BMP4, IL-7 or BMP4 + IL-7 for 6 h. The expression of FITC-Annexin V+/PI+ IELs in the IL-7 treatment group was significantly lower compared with that in the control group, whereas the expression of FITC-Annexin V+/PI+ IELs in the BMP4 treatment group was significantly higher compared with that in the control group. However, the expression of FITC-Annexin V+/PI+ IELs in the BMP4 + IL-7 treatment group exhibited no changes compared with the control group. Each experiment was repeated three times; 4-5 mice/group. P<0.05.