Protective effect of bone marrow mesenchymal stem cells in intestinal barrier permeability after heterotopic intestinal transplantation

Figure 1 Morphology and flow cytometry results of Lewis-derived bone marrow mesenchymal stem cells. A: First-passage bone marrow mesenchymal stem cells (BM MSCs); B: Second-passage BM MSCs; C: Third-passage BM MSCs (× 200 magnification); D: The proportion of CD90⁺ and CD450^- cells was approximately 95.48%; E: The proportion of CD29⁺ and CD34^- cells was approximately 99.82%; F: The proportion of RT1A⁺ and RT1B^- cells was approximately 99.87%.

Figure 2 Graft histopathology at different time points after heterotopic intestinal transplantation (HE staining, × 200). A: Normal intestine with normal villous architecture and glands in group A; B: Intestinal mucosa degradation and hemorrhage of the lamina propria, ulceration, decreased ratio of villus height and crypt height, aggravated lymphocyte infiltration, partial gland epithelial necrosis in group B at day 5 after operation; D: There were decreased intestinal mucosal villi with mild deformity and interstitial infiltration of inflammatory cells; E: The condition was aggravated 7 d after heterotopic intestinal transplantation, and there was epithelial degeneration, intestinal wall thinning and necrosis, and interstitial inflammatory cell infiltration in great quantities; C, F: Recovery of the damaged mucosa in group A at (C) day 5 and (F) day 7.

Figure 3 Ultrastructural characteristics of intestinal mucosa and tight junctions following heterotopic intestinal transplantation (magnification × 30000). A: Epithelial cells and tight junctions (TJs) (arrows) were intact in group A; B: Intestinal microvilli and TJs (arrows) were disrupted, and some microvilli were loose; C: Organelles were swollen with reduced electron density at day 5 after transplantation in group B; D: Microvilli and mitochondria of the endothelial cells were almost normal and TJs (arrow) were not disrupted at day 5 after transplantation in group C.

Figure 4 Occludin and zona occludens-1 protein expression after heterotopic intestinal transplantation. Occludin and zona occludens (ZO)-1 protein expression was significantly lower in group B than in group A (^aP < 0.05 vs group B at day 5: 0.2082 ± 0.0582 vs 0.5477 ± 0.0284; ^aP < 0.05 vs group B at day 7: 0.3415 ± 0.0128 vs 0.6387 ± 0.046). Occludin and ZO-1 protein expression was significantly higher in group C than in group B (^aP < 0.05 vs group B at day 7: 0.2674 ± 0.0128 vs 0.1352 ± 0.0142; ^aP < 0.05 vs group B at day 5: 0.7189 ± 0.0289 vs 0.4556 ± 0.0242). A: Group A (non-rejection); B: Group B (rejection); C: Group C (bone marrow mesenchymal stem cells therapy). β-actin was used as the loading control. Values shown are the mean ± SD.

Figure 5 Occludin and zona occludens-1 mRNA expression after heterotopic intestinal transplantation. Occludin and zona occludens (ZO)-1 mRNA expression was significantly lower in group B than in group A (^aP < 0.05 vs group B at day 5: 0.3135 ± 0.0168 vs 0.7011 ± 0.0128; ^aP < 0.05 vs group B at day 7: 0.2101 ± 0.0279 vs 0.5345 ± 0.0136). Occludin and ZO-1 mRNA expression was significantly higher in group C than in group B at day 5 (^aP < 0.05 vs group B at day 7: 0.3860 ± 0.0254 vs 0.1673 ± 0.0369; ^aP < 0.05 vs group B at day 5: 0.5727 ± 0.0419 vs 0.3598 ± 0.0242). A: Group A (non-rejection); B: Group B (rejection); C: Group C (bone marrow mesenchymal stem cells therapy). β-actin was used as the loading control. Values shown are the mean ± SD.

Figure 6 Graft tumor necrosis factor-α, interferon-γ, interleukin-10, and transforming growth factor-β levels. Graft tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), interleukin-10 (IL-10), and transforming growth factor-β (TGF-β) levels in group B were significantly decreased compared to that in group A at day 7 (17.2128 ± 0.4991 vs 12.8364 ± 0.7131, P < 0.05; 810.2637 ± 25.1175 vs 555.3763 ± 17.9702, P < 0.05; 80.3756 ± 2.5866 vs 59.9878 ± 2.1521, P < 0.05; 130.8756 ± 3.3428 vs 109.9878 ± 9.7968, P < 0.05). Graft TNF-α and IFN-γ levels in group C were significantly decreased compared to that in group B at day 7 (10.6473 ± 0.0710 vs 17.2128 ± 0.4991, P < 0.05; 545.1506 ± 31.9416 vs 810.2637 ± 25.1175, P < 0.05); graft IL-10 and TGF-β levels in group C were significantly increased compared to that in group B at day 7 (125.7773 ± 4.7719 vs 80.3756 ± 2.5866, P < 0.05; 234.5273 ± 9.3980 vs 545.1506 ± 31.9416, P < 0.05). A: Group A (non-rejection); B: Group B (rejection); C: Group C (BM MSC therapy). All values are mean ± SD (n = 6). ^aP < 0.05 vs group B.