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(m ALB), 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(Ca MKK-β), phosphoinositide 3-kinases(PI3 K), 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 2×10-6mol/L Ang Ⅱ. The primary human podocytes, human glomerular endothelial cells(HRGECs), and human proximal tubular epithelial cells(HK-2 s) were pre-incubated with sulfotanshinone sodium(Tan, 10 μg/m L) and/or calycosin-7-O-β-D-glucoside(Cal, 5 μg/m L). 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 significantly 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 m ALB 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 Ca MKK-β and the increased protein levels of PI3 K, 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-2 s and improved the level of e NOS 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.