OBJECTIVETo explore the effects of p38MAPK inhibitor SB203580 (SB) on the occurrence of acute GVHD and intestine damage after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in mice.

METHODSSixty BALB/c mice, as recipients, were randomized to control group, irradiation group, model group and intervention group. C57BL/6 mice, as donors, were raised to prepare the bone marrow cells (BMCs) and spleen cells (SCs), which were injected into irradiated recipients mice by tail vein. Except control group, other groups accepted 7.5Gy total body irradiation. Model group and intervention group were infused with BMCs 5×10⁶ and SCs 5×10⁵ by less than 4 h after irradiation. SB was injected into intervention group by intraperitoneally, but only DMSO for model group. The general status and survival rate of each group were evaluated. The expression of p-p38MAPK, Fas and FasL in intestine were determined by RT-PCR, Western blot and immunohistochemistry (IHC).

RESULTSThe weight changes of intervention group (13.00±0.50)% was significantly lighter than that of model group (25.00±0.75)% (P<0.05). The clinical score of acute GVHD in the intervention group (3.33±0.82) was significantly lower than that of model group (6.33±1.36) (P<0.05). The expression levels of p-p38MAPK, Fas and FasL in small intestine of intervention group (1.43±0.02, 0.81±0.03, 0.97±0.03) were lower than those of model group (1.76±0.05, 1.52±0.04, 1.48±0.04).

CONCLUSIONSB inhibited the activation of p38MAPK and Fas/ FasL signal pathway and alleviated the apoptosis of small intestine. And SB could relieve small intestine damages induced by allogeneic T lymphocytes.