Establishment of acute rejection model of rat kidney transplantation

Objective To establish experimental acute rejection model of rat kidney transplantation and to investigate its histological features. Methods In allograft group,Wistar rats and male SD rats were separately used as donors and recipients.In isograft group, SD rats served as both donors and recipients.The graft specimens were harvested at 1,3,5 and 7 days postoperatively.They were examined histologically after sectioning and staining with hematoxylin and eosin,Masson’s trichrome,periodic acid-Schiff reagent and periodic acid silver metheramine.Acute rejection was diagnosed according to the Banff 97 classification.The rejection score was classified semiquantitatively into 7 grades from 0 to 6 according to the method stated by Watanabe:0=normal,1=borderline changes,2=ⅠA,3=ⅠB,4=ⅡA,5=ⅡB,and 6=Ⅲ by Banff classification. Results The semiquantitative scores at 1,3,5 and 7 days after operation were 0.50±0.54, 1.33±0.82,3.50±1.05,4.33±0.82 in allograft group and 0.33±0.52,0.67±0.52,0.67±0.52, 0.67± 0.52 in isograft group,respectively. In allograft group,the scores at 3,5 and 7 days postoperatively were significantly higher than those on the first day (P0.05),the scores at 5 and 7 days postoperatively were significantly higher than those at 3 days (P0.05),but it was not significantly different between 5 and 7 days after operation (P0.05).In isograft group,the scores at 1,3,5 and 7 days postoperatively were not significantly different (P0.05). Conclusions When SD rats serve as both donors and recipients,the rejection is mild because of their good tissue compatibility.The rejection of Wistar-SD rat kidney transplants is rapid and severe, which can serve as good animal model of acute rejection.