Objective:To investigate the relationship of gene expression and activity of chymase and Ang Ⅱwith nephropathy in the streptozotocin(STZ)-induced diabetic hamsters.Methods:Thirty male hamsters were randomly divided into two groups:normal controls and diabetic rats.Diabetes mellitus was induced in rats by intraperitoneal streptozotocin injection.The nephritic ultrastructure was observed with electron microscope.The levels of blood glucose

lipoprotein were measured by biochemical methods.The level of angiotensin Ⅱ(Ang Ⅱ) and the activity of chymase and angiotensin-convertion enzyme(ACE) were measured by radioimmuno assay.Reverse transcription polymerase chain reaction(RT-PCR)was used to determine chymase gene expression(corrected by β-actin).Results:Chymase activity in DN group was much higher than that in the control group(0.82±0.05) U vs(0.49±0.03) U

P<0.01.This was accompanied by increased angiotensin Ⅱ(88.6±17.5) pg/mg tissue vs(48.2±15.3) pg/mg tissue

P<0.01 and chymase mRNA(1.81±0.09) vs(4.90±0.79)

P<0.01.But the activity of ACE was unchanged

indicating an alternative non-ACE dependent way of angiotensin Ⅱgenerating.Conclusion:In diabetic hamsters

the gene expression and activity of chymase are much higher than those in the control group

accompanying higher level of angiotensin Ⅱ.This reflects another mechanism was involved except for the classic ACE pathway to activate the intrarenal RAS in the progress of diabetic nephropathy(DN).