[Therapeutic effect of allogenic bone marrow transplantation in acute TNBS-induced colitis]

Bone marrow-derived cells (BMDC) contribute to tissue maintenance under many kinds of pathologic conditions. We carried out a study to see how BMDC play a role in the treatment of experimental murine colitis.

We divided the animals into 3 groups and treated them with 50% ethanol (control group), 2,4,6-trinitrobenzene sulfinic acid colitis (TNBS group), and TNBS+bone marrow transplant (BMT group). To induce colitis, TNBS (5.0 mg/mouse) dissolved in 50% ethanol was injected into anus weekly for two weeks. Bone marrow transplantations were performed using bone marrow of male transgenic mouse (donor) with green fluorescence protein (GFP) into female wild type mouse (recipient) three weeks before TNBS instillation. All animals were sacrificed, and colons were extracted one week after the last TNBS instillation. We measured microscopic scores of mucosal injury and investigated the GFP expression for bone marrow engraftment. The immunostaining of vimentin and alpha-smooth muscle actin (alpha-SMA) for myofibroblasts was performed.

The score of mucosal injury in the TNBS group was much more severe than those in control, and reduced significantly by BMT (p<0.05). GFP-positive cells were almost deposited in pericryptal niche of BMT group but not at all in both control and TNBS group. Most of myofibroblasts stained with both vimentin and SMA also infiltrated into pericryptal niche. But, the number of myofibroblasts stained with vimentin and SMA in both control and TNBS group was smaller than that in BMT group.

BMDC deposited on pericryptal niche might have a significant role in repairing acute experimental murine colitis.