Objective To observe the effect of blood-activating and stasis-dissolving herbs on rats with diabetic nephropathy （DN） and its mechanism.Methods Forty-six healthy male Sprague-Dauley rats were randomized into normal group （10 rats） and DN model group （36 rats） was established by streptozotocin injection into abdominal cavity

which was subrandominzed into model group

benazepril group

and herbal group

12 rats in each. One week after modelling

the treatment groups were medicated by gavage in the same volume

and the normal and model groups were given distilled water of the same volume in succession for 23 weeks

and then killed. HE and PAS staining was done to observe the pathological changes of renal tissues

radioimmunoassay was used to determine the level of angiotensinⅡ（Ang Ⅱ）

ultraviolet spectrophotometry was applied to measure the activity of angiotensin conversion enzyme （ACE）

and immunohistochemistry was employed to test the expressions of ACE and ACE-related carboxypeptidase （ACE2） in the renal tissues of rats.Results Compared with the model group

the thickened glomerular basement membrane

increased mesangial cells

proliferated mesangial matrix

and enlarged mesangial area became lightened. In addition

herbal treatment could decrease the level of AngⅡand active ACE （P<0.05） and increase the expression of ACE2 （P<0.05）.Conclusion The blood-activating and stasis-dissolving herbs have the function to reduce the pathological damage of DN

possibly partially through the regulation of renin angiotensin system.