Objective  To establish a rat model of acute antibody-mediated rejection (AMR) in kidney transplantation and investigate the preventive effect of dihydroartemisinin (DHA) on acute AMR.

Methods  BN rats were used as donors and Lewis rats as recipients. Kidney transplantation was performed 2 weeks after skin transplantation for sensitization. After establishing the acute AMR model in rat kidney transplantation, the recipients of experimental groups included the syngeneic kidney transplantation group (6 rats), the allogeneic kidney transplantation group (6 rats), the syngeneic skin transplantation followed by kidney transplantation group (12 rats), and the allogeneic skin transplantation followed by kidney transplantation group (24 rats). The groups for investigating the preventive effect of DHA on acute AMR included the control group (allogeneic skin transplantation followed by kidney transplantation) and the DHA group (allogeneic skin transplantation followed by kidney transplantation + DHA), with 12 rats in each group. The survival time of recipient rats, serum donor-specific antibody (DSA) levels and graft pathological changes were used to identify the acute AMR model. On this basis, DSA levels, pathological changes in the transplant kidneys and peripheral blood B-cell levels were detected to assess the preventive effect of DHA on acute AMR.

Results  Compared with the allogeneic kidney transplantation group, skin transplantation sensitization significantly shortened the survival time of recipient rats (P<0.01). Compared with the syngeneic skin transplantation followed by kidney transplantation group, the allogeneic skin transplantation followed by kidney transplantation group showed significantly elevated serum DSA-IgG levels from 7 days after skin transplantation to 5 days after kidney transplantation (P<0.01), and significantly elevated DSA-IgM levels at 7 and 14 days after skin transplantation(all P<0.01). The transplant kidneys in the allogeneic skin transplantation followed by kidney transplantation group showed a small number of inflammatory cell infiltrations, tubular necrosis, capillaritis, and C4d deposition starting from 1 day after kidney transplantation, with these pathological changes worsening as the post-transplantation days increased. The kidney damage became significant starting from 3 days after transplantation. The above pathology manifestations were consistent with the characteristics of acute AMR. On the basis of establishing the acute AMR model, DHA treatment significantly prolonged the survival time of recipient rats (P<0.01) , and reduced serum DSA-IgG and DSA-IgM levels. DHA treatment significantly alleviated the pathological manifestations of acute AMR, including kidney damage, inflammatory cell infiltration, capillaritis and tubular necrosis, and also reduced C4d deposition in the transplant kidneys, inflammatory cell infiltration and peripheral blood CD19⁺ B-cell levels.

Conclusions  An acute AMR model is established by performing kidney transplantation 2 weeks after allogeneic skin transplantation in rats. It is discovered that DHA has immunosuppressive effects and may effectively prevent acute AMR, which provides a new strategy for the management of clinical AMR.