Abstract
AIM: To investigate whether the stromal cell-derived factor-1α (SDF-1α)/chemokine receptor 4 (CXCR4) axis mediates the therapeutic effects of bone marrow-derived mesenchymal stem cells (BMSCs) for 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-colitis in rats.
METHODS: BMSCs were isolated from Sprague-Dawley (SD) rats and identified by flow cytometry. Lentivirus transfection was applied to over-express CXCR4/GFP (Ad-CXCR4-BMSCs) or null/GFP (Ad-GFP-BMSCs), and Western blot was applied to detect the protein expression of CXCR4 in BMSCs. Thirty-two SD rats were randomly divided into four groups (n = 8 for each group): a control group, a model group, an Ad-GFP-BMSCs group and an Ad-CXCR4-BMSCs group. Experimental colitis was induced with TNBS, and Ad-CXCR4-BMSCs or Ad-GFP-BMSCs were administered intravenously. One week after cell therapy, the colons were harvested. The expressions of GFP and SDF-1α in colon tissues were measured by Western blot and immunofluorescence.
RESULTS: The cell viability was approximately 90%, and 80% of BMSCs steadily carried the GFP protein after lentivirus transfection. Compared with the control group, the protein expression of SDF-1α was distinctly increased in injured colon in the model group. One week after cell therapy, Ad-GFP-BMSCs failed to colonize in the inflamed colon and had no beneficial effect on pathological inflammation score compared to the vehicle group (3.50 ± 0.53 vs 3.62 ± 0.52, P > 0.05). Compared with the model group, Ad-CXCR4-BMSCs signally down-regulated the disease activity index (2.71 ± 0.28 vs 3.88 ± 0.17, P < 0.01) and pathological inflammation score (2.25 ± 0.71 vs 3.62 ± 0.52, P < 0.01). Compared to the Ad-GFP-BMSCs group, the protein expression of GFP was significantly increased in the Ad-CXCR4-BMSCs group (0.70 ± 0.34 vs 0.10 ± 0.12, P < 0.01).
CONCLUSION: Our findings suggest that the SDF-1α/CXCR4 axis plays a crucial role in BMSCs migration toward injured colon, which may provide an attractive target for BMSCs-based therapies for IBD.
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