Abstract： Objective To investigate the effects of ligustrazine on renal tubulointerstitial injury in adriamycin nephrosis rats and its mechanism.Methods Forty male Sprague-Dawley rats were randomly divided into sham-operation group,model group,ligustrazine group and Benazepril group.The rat nephropathy model was established by adriamycin injection and unilateral nephrectomy.The 24-hour urinary protein excretion at the start,2nd,4th,6th weekends was analyzed.All rats were sacrificed at the 6th weekend,and then the renal function and the tubulointerstitial pathological injury were examined.Immunohistochemistry was used to measure the expression of ET-1.Results The 24-hour urinary protein excretion [ (30.07 ±2.12) mg/24 h,(201.83 ± 8.63 ) mg/24 h,( 470.70 ± 58.79 ) mg/24 h ] ( at the 2th,4th,6th weekend),blood urea nitrogen[ BUN( 20.20 ± 2.65 ) mmol/L],serum creatinine[ Scr ( 86.79 ± 2.20 ) μmol/L),tubulointerstitial pathological injury (4.38 ± 0.26) and the expression of ET-1 ( 126.92 ± 3.63 )in model group were significantly higher than those in sham-operation group [ ( 6.75 ± 2.07 ) mg/24 h,( 8.28 ± 0.71 ) mg/24h,( 25.37 ± 4.30) mg/24 h,( 8.93 ± 1.05 ) mmol/L,(49.00 ± 5.34 ) μmol/L,1.06 ± 0.19,32.09 ± 3.71,P ＜ 0.01 ].Compared with model group,the 24-hour urinary protein excretion [ ( 176.93 ± 9.20)mg/24 h,( 270.45 ± 60.21 ) mg/24 h) ( at the 4th,6th weekend),BUN [ ( 13.75 ± 2.60 ) mmol/L ],Scr [ ( 62.49 ±3.29)μmol/ L ],Renal tubulointerstitial pathological injury (2.78 ± 0.10) and the expression of ET-1(57.44 ± 4.98 ) were significantly decreased in ligustrazine group( P ＜ 0.01 ).Conclusions Ligustrazine can downregulate the expression of ET-1 and decreased urinary protein excretion,leading to reduce tubulointerstitial inflammation and fibrosis.