Objective To investigate the pathophysiologic role of T lymphocytes in renal ischemia-reperfusion injury in mice.Methods BALB/c wild-mice(group A, n = 24) and BALB/c nude-mice(group B,n = 24) were divided into four groups(n = 6),respectively,the groups A-1 to A-4 and groups B-1 to B-4.Bilateral renal pedicles were occluded by microvascular clamps for 45 minutes.Then the kidneys were reperfused.Samples were collected at sham operation and 24 h,48 h and 72 h after IRI.Serum creatinine(Scr),urine protein concentration,renal histology and splenic CD3~ /CD4~ /CD8~ positive cells(group A) were examined,respectively.Results\ Scr and urine protein concentration increased and histological injury was observed in group A-(2-4) and B-(2-4).The injury in group A were more severe than that in group B(P<0.05).FACS analysis showed,that in comparison with group A-1,percentage of splenic CD3~ T cells in group A-2 and A-3 increased significantly(P<0.05),but a similar ratio of CD4~ /CD8~ between group A1 and group A-(2-3)(P>0.05)).Conclusion T lymphocytes play an important pathophysiologic role in renal ischemia-reperfusion injury,and may mediate post-ischemic decline in renal function and lead to histological injury.