Protective Effects of Combination of Radix Astragali and Radix Salviae Miltiorrhizae on Kidney of Spontaneously Hypertensive Rats and Renal Intrinsic Cells.

OBJECTIVE

To evaluate the effects of combination of Radix Astragali (RA) and Radix Salviae Miltiorrhizae (RS) on kidney of spontaneously hypertensive rats (SHRs) and renal intrinsic cells.

METHODS

SHRs were intragastrically administrated with RA (5.09 g/kg) and RS (2.55 g/kg) either alone or with combination for 4 weeks; valsartan (13.35 mg/kg) was used as a positive control. Blood pressure and renal ultrasonography were monitored periodically. The biomarkers [microalbumin (mALB), cystatin ^C, angiotensin II (Ang II), interleukin-1 beta (IL-1β), and β2-microglobulin (β2-Mg), etc.] in serum and urine were measured by enzyme-linked immunosorbent assay (ELISA). The protein expressions [phosphorylated adenosine 5'-monophosphate-activated protein kinase-α1 (p-AMPKα1), sestrin-β, calcium/calmodulin-dependent protein kinase kinase-β (CaMKK-β), phosphoinositide 3-kinases (PI3K), serine-threonine protein kinase 1 (AKT1), and vascular endothelial growth factor receptor 2 (VEGFR2)] in renal cortex were determined by Western blot. In vitro, the hypertensive cellular model was established by applying 2×10 mol/L Ang ^II. The primary human podocytes, human glomerular endothelial cells (HRGECs), and human proximal tubular epithelial cells (HK-2s) were pre-incubated with sulfotanshinone sodium (Tan, 10 μg/mL) and/or calycosin-7-O-β-D-glucoside (Cal, 5 μg/mL). The cellular viability and apoptosis were assayed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and Annexin V/PI staining, respectively. The level of endothelial nitric oxide synthase (eNOS) in culture supernatant was determined by ELISA.

RESULTS

RA+RS signifificantly decreased the diastolic blood pressure, renal vascular resistance index, and parenchymal thickness, increased 24 h urinary volume as well as lowered the levels of urine mALB and serum cystatin ^C, IL-1β and β2-Mg of SHRs (P <0.05 vs. SHRs). The decreased protein levels of p-AMPKα1, sestrinβ and CaMKK-β and the increased protein levels of PI3K, AKT1 and VEGFR2 in renal cortex of SHRs were normalized after RA+RS treatment (P <0.05). In vitro, Tan and Cal attenuated the Ang II-induced abnormal proliferation and increased the apoptosis of HRGECs and HK-2s and improved the level of eNOS in culture supernatant. Whereas, neither of them showed powerful effect on podocyte.

CONCLUSION

The combination of RA and RS had potential effects on alleviating the renal damages of SHRs and the renoprotection was independent of blood pressure level.