Abstract: AIM: To investigate the effects of diatrizoate on the expression of endothelin receptor A (ETAR) in cardiac myocyte of diabetic nephropathy SD rats.METHEDS: 32 male SD rats (220-280 g) were randomly divided into four groups:8 normal control rats (Con group) with sham surgeon operation ;the other 24 were diabetic rats which were induced by intraperitoneal streptozotocin (35 mg·kg^-1 body weight) at one dose after they were uninephrectomized for 2 weeks.At the end of the eighth week, the diabetic rats were divided into 3 groups at random:(DM group) ;diabetic rats plus diatrizoate injection (10 ml·kg^-1) through tail vein of rats (CM group) ;BQ123 treated group (BQ group) which were injected the BQ123 (1 mg·kg^-1) before being injected the diatrizoate, while the Con group were only given the sterile water.ETARwas examined by reverse transcription polymerase chain reaction (RT-PCR) and western blot.RESULTS: Both RT-PCR and Western blot analysis indicated that ETAR had been upregulated in CM, DM and BQ groups compared with that in Con group (P<0.05) ;especially in CM group.BQ123 could downregulate the expression of ETAR gene induced by diatrizoate .CONCLUSION: Increasing ETAR may affect cardiac function induced by radiocontrast media diatrizoate under diabetic nephropathy conditions.However, BQ123 can downregulate the expression of ETAR gene induced by radiocontrast media diatrizoate and improve cardiac function.

Key words: radiocontrast media, diatrizoate, diabetes mellitus nephropathy, ETAR, Western blot, RT-PCR