Objective To study the changes of blood glutathione peroxidase (GSH-px),superoxide dis-mutase (SOD),malondialdehyde (MDA) and pathological tissues in the rat contrast-induced nephropathy (CIN) model,and to determine the role of oxidation mechanism in CIN.Methods A total of 40 adult male SD rats were selected and divided into three big groups and five small groups.After constructing the model,six rats with good status were taken from each group for conducting the experiment.The serum GSH-px,SOD and MDA levels were measured,the renal tissue biopsy was performed and the morphological changes of kid-ney cells were compared.Results There was no statistically significant difference in the baseline data among the blank control group,the control group and the experimental group (P>0.05).There was no statistically significant difference in serum GSH-px,SOD and MDA levels before model construction,at 24,48 h after model construction between the blank control group and the control group (P>0.05).There were statistical-ly significant differences in serum GSH-px,SOD and MDA levels of the experimental group between before model construction and after model construction (P<0.05).There was no statistically significant difference in serum GSH-px,SOD and MDA level in the experimental group between at 24 h after modelling and 48 h af-ter modeling (P>0.05).There was no statistically significant difference in serum GSH-px,SOD and MDA levels at 24 h after modeling among the three groups (P>0.05).There were statistically significant differ-ences in serum GSH-px,SOD and MDA levels at 48 h after modeling among the three groups and their pairs (P<0.05).The pathological sections of the blank control group and control group showed no obvious abnor-mal changes in glomeruli,renal tubule and renal interstitium.Renal interstitial fibrosis and inflammatory cell infiltration were seen after 24 h in the experimental group,but there was no obvious change in the renal tu-bules.After 48 h,moderate focal-like atrophy of renal tubules,epithelial cell granule degeneration and vacuolar changes were obviously seen.Conclusion The oxidative stress mechanism plays a role in CIN.The contrast a-gent acute renal injury mainly acts on the renal tubules and renal interstitium,and there is no obvious damage to the glomeruli.