To investigate the effect and mechanism of Compound Herba Desmodii Mixture on renal function in rats with calcium oxalate calculi.Methods:A total of 40 male SPF SD rats were randomly divided into a study group and a control group, with 20 rats in each group.The model of calcium oxalate nephrolithiasis was induced by L-hydroxyproline injecting in the study group.The rats were treated with Compound Herba Desmodii Mixture for 28 days.Urine samples were collected from the control group and study group before modeling, 1 day after modeling and 28 days after modeling.The urine volume, urinary protein, urinary creatinine and urinary calcium were detected.At the same time of urine samples taking, 2 mL of caudal vein blood were collected from the 2 groups.Serum creatinine, blood urea nitrogen and other renal function indexes were detected.The left kidney was made into 10% homogenate to detect the contents of MDA, SOD and GSH-Px.The right kidney was sectioned and the expressions of osteopontin(0PN)and transforming growth factor-beta(TGF-beta)were detected by immunohistochemistry.Results:Compared with those of the control group, the urine volume of the study group one day after the establishment of the model decreased, while the urine protein, urine creatinine, urine calcium, serum creatinine and serum urea nitrogen levels of the study group one day after the establishment of the mode were increased(P<0.05).Compared with those of the same group before modeling, the urine volume of the study group 1 day after modeling decreased, while the urine protein, urine creatinine, urine calcium, serum creatinine and serum urea nitrogen levels of the study group 1 day after modeling increased(P<0.05).Compared with those of the same group one day after model was established, the urine volume of the study group 28 days after modeling increased, while the urine protein, urine creatinine, urine calcium, serum creatinine and serum urea nitrogen levels of the study group 28 days after modeling decreased(P<0.05).Compared with those of the control group, the content of MDA and the positive expression rate of 0PN and TGF-beta in renal tissue of the study group increased, while the content of SOD and GSH-Px of the study group decreased(P<0.05).Conclusion:Compound Herba Desmodii Mixture can improve renal function in rats with calcium oxalate calculi, and improvement of oxidative stress and inflammation may be its mechanism.