Objective: To investigate the treatment effect of Yiqi Jiedu Huoluo formula(YQJDHL) in rats with early diabetic nephropathy (DN) and observe its effect on transforining growth factor-β(TGF-β)/Smad pathways. Method: Totally 72 SPF healthy male SD rats were used to establish diabetes mellitus (DM) models by tail injection of streptozotocin (STZ). Then according to the blood sugar levels

the rats were randomly divided into model group

YQJDHL prevention group (2.4 g·kg-1·d-1)

YQJDHL low dose group and high dose group (2.4

7.2 g·kg-1·d-1)

positive drug group (benazepril hydrochloride

10 mg·kg-1·d-1)

another normal group was also set up

n=12 in each group. In the YQJDHL preventive group

YQJDHL compound formula was immediately given after DM models were made. While in YQJDHL high and low dose groups and positive drug group

the medicine was given two weeks after the DM models were made

that was immediately after DN models were made. Four weeks after intragastrical administration of YQJDHL formula

24 h urine of rats was collected to determine the urine trace albumin

and the blood was taken by abdominal aorta puncture to determine blood glucose in rats;renal tissue samples were collected to observe the renal pathological changes by htoxylin-eosin (HE) staining method;the effects of YQJDHL TGF-β1

Smad3/7 mRNA and protein expression levels in the kidney tissues of early DN rats were observed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assay. Result: As compared with the normal group

the blood glucose and urine trace albumin were significantly increased in rats of model group;TGF-β1 and Smad3 expression levels were significantly increased;Smad7 expression level was significantly reduced (P < 0.01);and the renal pathological changes were obvious in pathological observation. QJDHL treatment groups and preventive group could reduce the blood glucose and urine trace albumin in rats

reduce TGF-β1 and Smad3 expression levels in kidney tissues

and increase Smad7 expression (P < 0.05

P < 0.01);in addition

renal pathological changes were significantly improved. Conclusion: The results showed that the YQJDHL formula had the treatment and prevention effect for the DN

and its mechanism of action may be associated with TGF-β/Smad signaling pathways.