Objective To evaluate the nephrotoxicity induced by radiographic contrast media with different osmolality in rats with hypercholesterolemia, and to explore the protective effect of pentoxifylline. Methods Forty-eight healthy SD male rats were randomly divided into normal dietary group (NN, n =8) and high cholesterol supplemented dietary group (H, 4% cholesterol and 1% cholic acid, n=40). At the end of 8th week, the rats with high cholesterol diet were randomly divided into five subgroups (n=8, respectively): high cholesterol diet group(HN), high cholesterol plus iso-osmolar contrast media (iodixanol, IOCM) group (HI), high cholesterol plus low-osmolar contrast media (iohexle, LOCM) group (HL), high cholesterol diet plus high-osmolar contrast media (diatrizoate, HOCM) group (HH) and high cholesterol plus HOCM plus pentoxifylline group (HHP). Forty-eight hours after contrast media injection, the rats were executed and blood samples were prepared to determine total cholesterol, triglyceride, serum creatinine, creatinine clearance(Ccr), fractional excretion of sodium and potassium(FeNa, FeK), and angtension Ⅱ (Ang Ⅱ) levels. The renal injury was assessed by HE staining and TUNEL staining, respectively. The expression of NF-κB protein in the renal tissue was detected by using immunohistocbemical method. Results An increase of cholesterol was observed in all the rats with high cholesterol diet. Scr, FeNa%, FeK% and Ang Ⅱ levels of rats in HH group were obviously higher than those in HL and HI groups respectively. Ccr in HH group [(0.11±0.02) ml·min-1·(100 g)-1] was significantly lower than that in HHP group [(0.43±0.03) ml·min-1·(100 g)-1], HL group [(0.25±0.02) ml·min-1·(100 g)-1] or HI group [(0.27±0.03) ml·min-1,(100 g)-1] (P<0.05). TUNEL staining showed that the pewentage of apoptotic cells in HH group [(89.60±6.40)% ] was higher than that of the other groups [NN (2.40±0.77)%, HN (5.60±1.08)%, HHP (8.91±1.44)%, HL (63.34±11.97)% and HI (61.50±9.40)%]. Immunohistochemistry staining showed that the average gray value of NF-κB positive cells in HH group decreased (P<0.05). There were no significant differences of all indices between HL and HI groups (P0.05). Conclusions Contrast media can cause kidney injuries in the rats with hypercholesterolemia. PTX can protect the renal tissue from nephrotoxicity induced by HOCM in hypercholesterolemia.