Influence of different kinds of pretreatment regimen on graft versus host disease in rat models

Objective: To discuss the influence of different total body irradiation (TBI) doses on incidence and severity of graft versus host disease (GVHD). Methods: Twenty rats were randomized to A, B, C, D groups which all received TBI. Groups A and B received 2 Gy while groups C and D 6 Gy. Groups A and C received bone marrow cells from donor rats. Groups B and D received equivalent dose of NS serving as control for comparison. Life span, clinical GVHD manifestations and pathologic changes in the colon and liver were evaluated. Results: The mean life span for group A was 24.6 days as compared with 17.8 days of group C, with much longer survival in the former group (P<0.01). There were significant differences in clinical GVHD score and pathologic changes between groups A and C, with severer clinical GVHD manifestations and pathologic changes in the latter group (P<0.01). Conclusions: The incidence and severity of graft versus host disease is much lower in rats which received lower total body irradiation (TBI) dose than those with higher TBI dose