OBJECTIVETo observe the effect of Chinese herbs for stasis removing and collaterals dredging (CHSRCD) upon angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas axis in the renal cortex of diabetic nephropathy rats.

METHODSTotally 89 male Sprague-Dawley rats were randomly divided into the blank control group (C group, n=22), the high-glucose high-fat control group (H group, n=10), and the streptozotocin (STZ)-injecting group (n=57). The diabetes rat model (n=50) was induced by feeding high-glucose high-fat diet in combination with intraperitoneal injection of STZ, which were further divided into the model group (M group, n=24), the irbesartan group (I group, n=13), and the CHSRCD (Z group, n=13). Rats in I and Z groups were intragastrically fed with suspension of irbesartan and CHSRCD, once daily for 16 weeks. Equal volume of drinking water was administrated to rats in the rest groups. Blood glucose and 24 h urine protein quantitation were tested at four time points. And the mRNA expression of ACE2 and Mas at various time points was detected by Real-time PCR, immunohistochemical assay, and Western blot. Quantitative analyses of ACE2 and Mas protein expression were performed at the end of week 16.

RESULTSCompared with the C group, blood glucose increased in the H and M groups (P < 0.01). It was higher in the H group (P < 0. 01). 24 h urine protein quantitation at different time points increased in the M group, and it was higher than that in the H group (P < 0.05). Compared with the M group, 24 h urine protein quantitation decreased at the end of week 8 in the I group, and at the end of week 8 and 16 in the Z group (P < 0.05). It was lower in the Z group than in the I group at the end of week 16 (P < 0.05). Compared with the C and H groups, the expression of ACE2 mRNA in the renal cortex was lower in the M group at the end of week 16 (P < 0.01). Compared with the M group, it was higher in the Z group (P < 0. 01). There was no statistical difference in the expressions of Mas mRNA at the end of week 16 between the C group and the M group (P > 0.05). It was lower in the M group than in the H group (P < 0.05). It was higher in the Z group than in the M group (P < 0.05), and higher than in the I group (P < 0.05). The expression of ACE2 and Mas protein in the M group decreased as time went by. The expression quantitation of ACE2 and Mas protein at the end of week 16 was lower in the M group than in the C group (P < 0.05). Compared with the M group, ACE2 expression of the Z group and Mas of the I and Z groups increased more significantly (P < 0. 05).

CONCLUSIONCHSRCD could play a role in renal protection for diabetic nephropathy rats by up-regulating the mRNA and protein expression of ACE2 and Mas, promoting the ACE2-Ang-(1-7)-Mas axis, and lowering urinary protein.