Objective To observe the influence of low protein diet with α-keto acid on kidney sclerosis and renin-angiotensin system in renal ablation rats. Methods Chronic renal failure rat model was established by renal ablation in 30 male SD rats,then the animals were randomly assigned to the following diet groups:normal protein group (NPD:18%casein protein),low protein group (LPD:6%casein protein) and supplemented low protein group (LK:5%casein protein+1%α-keto acids).Ten male SD sham-operated rats received 18%casein protein as control.All the rats were killed at the end of the 12th week.Pathologic changes were assessed by PAS staining.Ang II in homogenate and plasma were measured by radioimmunoassay and ELISA respectively.Immunohistochemistry and Western blotting were used to detect the protein expression of TGF-β1,renin and AT1R.Real-time PCR was used to detect the gene expression of renin and ATla,the main subtype of AT1 receptor. Results Body weight,total protein and serum albumin had not significant difference among the four groups(all P>0.05).Serum creatinine and proteinuria of nephrectomized rats were significantly higher compared to the control group (all P<0.05).Proteinuria of the LK group was lower than that of NPD and LPD groups (all P<0.05).Pathological results indicated fibrosis indices were significantly improved after LPD and LK intervention.Expressions of renin,Ang II and AT1R in LK group were significantly lower than those in NPD group (all P<0.05). Conclusions Low protein diet with α-keto acids supplement therapy exhibits renal protective effects of reducing urine protein excretion and improving renal fibrosis,which might be related to the attenuation of local renin-angiotensin system in activity nephrectomized rats.