Abstract: Objectives To investigate if leflunomide improves the immune status and renal function of BXSB lupus mice,and provide experimental evidences for the treatment of systemic lupus erythematosus (SLE) by leflunomide.Methods Forty-eight 3-month-old BXSB lupus mice were divided into four groups including leflunomide group,cyclophosphamide group,dexamethasone group and saline group.The amount of urinary protein was determined before treatment.After treatment,the amount of urinary protein,serum blood urea nitrogen (BUN),serum creatinine (Cr) level,anti-dsDNA antibodies and immune complex in renal glomeruli were measured.Results Before treatment,the amount of urinary protein had no significant difference among the four groups (P>0.05).After treatment,the amount of urinary protein and anti-dsDNA antibodies level in leflunomide group were significantly lower than those in dexamethasone and saline groups (P<0.01).Serum BUN and Cr level as well as immune complex in renal glomeruli in leflunomide group were significantly lower than those in other groups (P<0.05 or P<0.01).As compared with the saline group,leflunomide significantly prolonged the survival rate of BXSB mice (P<0.05).Conclusion Leflunomide can improve immune status and renal function of BXSB lupus mice,and delay their disease progression.

Key words: Lupus erythematosus,systemic, Animal testing alternatives, Leflunomide