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

AIM:To explore the protective effect of bone marrow mesenchymal stem cells(BM MSCs)in the small intestinal mucosal barrier following heterotopic intestinal transplantation(HIT)in a rat model.METHODS:BM MSCs were isolated from male Lewis rats by density gradient centrifugation,cultured,and analyzed by flow cytometry.The HIT models were divided into a non-rejection group,saline-treated rejection group(via penile vein),and BM MSC–treated group(via penile vein).Intestinal mucosal barrier injury was estimated by diamine oxidase(DAO)and D-lactic acid(D-LA)expression levels.Tumor necrosis factor-α(TNF-α),interferon-γ(INF-γ),interleukin-10(IL-10),and transforming growth factor-β(TGF-β)were detected by enzyme-linked immunosorbent assay.Ultrastructural change of tight junctions(TJs)was observed under transmission electron microscope.Expression levels of the TJ proteins occludin and zona occludens(ZO)-1,affected by the inflammatory factors,were measured using real-time polymerase chain reaction and Western blotting.RESULTS:The pathological score at each time point after surgery indicated significantly less serious injury in the BM MSCs-treated group than in the rejection group(P<0.05).In the former,graft levels of DAO and D-LA were reduced,and TNF-αand INF-γproduction was inhibited(at day 7:10.6473±0.0710vs 17.2128±0.4991,P<0.05;545.1506±31.9416vs 810.2637±25.1175,P<0.05).IL-10 and TGF-βproduction was increased greatly(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).There was increased expression of occludin and ZO-1 protein(at day 7:0.2674±0.0128 vs 0.1352±0.0142,P<0.05;at day 5:0.7189±0.0289 vs 0.4556±0.0242,P<0.05)and mRNA(at day 7:0.3860±0.0254 vs 0.1673±0.0369,P<0.05;at day 5:0.5727±0.0419 vs0.3598±0.0242,P<0.05).CONCLUSION:BM MSCs can improve intestinal barrier permeability,repair TJs,and increase occludin and ZO-1 protein expression.With altered cytokine levels,they can protect the intestinal mucosa after transplantation.