Objective To observe the possible mechanism of Modified Zhenwu Decoction（ 真武汤） in treating diabetic nephropathy（ DN）. Methods A total of 40 male SD rats were selected and randomly and equally divided into normal control group（ NC group）

model control group（ DN group）

low dose of Zhenwu Decoction（ 真武汤）group（ EL group）

high dose of Zhenwu Decoction group（ EH group）. The rat models of DN were established by the single injection of streptozotocin（ STZ）. The rats in EL group and EH group were respectively administered with Zhenwu Decoction 2. 45 g/（ kg· d） and 9. 8 g/（ kg · d）

while NC group and DN group were administered with equal volume distilled water once a day. After 16 weeks’ administration

the blood urea nitrogen（ BUN）

serum creatinine（ Scr）

urine creatinine（ Ucr） levels and 24 h urine protein quantitation in rats of each group were determined

and mesangial positive target integrated optical density（ IOD）

the expressions of insulin-like growth factor 1（ IGF-1） protein and mRNA in renal tissue were detected. Results Compared with NC group

the 24 hours urinary protein quantitative

levels of BUN and serum Scr in DN group were significantly increased

and the level of Ucr was significantly decreased

and the IOD was significantly increased. The kidney basement membrane was thickened obviously

mesangial cells were obviously proliferated and nodular sclerosis was formed. The IGF-1 protein and mRNA expressions were increased significantly in DN group（ P < 0. 05）. Compared with the DN group

the levels of 24 hours urinary protein quantitative

BUN and Scr in EL and EH groups were significantly decreased

and the level of Ucr was significantly increased. The IOD was significantly decreased

and the pathological damage of kidney tissue was significantly alleviated. The IGF-1 protein and mRNA expressions were decreased significantly（ P < 0. 05）. The changes of EH group were more obviously than EL group. Conclusion Modified Zhenwu Decoction can reduce the levels of24-hour urine protein

BUN and Scr

increase the levels of Ucr

and alleviate the pathological damage of kidney tissue in diabetic nephropathy rats. The molecular mechanism may be related to the regulation of Zhenwu Decoction on IGF-1 expression.