Protective effect of astragalosides from Radix Astragali on adriamycin-induced podocyte injury

Abstract

Nephrotic syndrome (NS) is the most common kidney disease in clinical practice and may lead to end-stage renal failure. Astragalosides (AST) have been clinically tested for the treatment of NS, but their mechanism of action has remained to be elucidated. The aim of the present study was to investigate the effect of AST on the structure and function of podocytes with adriamycin (ADR)-induced damage and to elucidate the underlying molecular mechanisms. The mouse podocyte clone 5 (MPC5) immortalized mouse podocyte cell line was treated with 0.5 µmol/l ADR to establish a podocyte injury model. The MPC5 podocytes were divided into a control group, a podocyte injury group and a low-, medium- and high-concentration AST treatment group. The results indicated that the survival rate of the podocyte injury group was significantly decreased compared with that in the control group and each AST-treated group had an increased survival rate compared with that in the podocyte injury group. Furthermore, each dose of AST significantly inhibited the ADR-associated increases the levels of lactate dehydrogenase and malondialdehyde and the decrease in the activity of superoxide dismutase in MPC5 podocytes. In addition, AST improved the migration ability of MPC5 podocytes and suppressed the cytoskeletal rearrangement associated with ADR-induced damage. Furthermore, matrix metalloproteinase (MMP)-2 and -9 were decreased in the podocyte injury group, which was inhibited by different concentrations of AST. Thus, AST was able to maintain the balance of oxidative stress in podocytes cultured with ADR and protect them from ADR-induced injury. The mechanism may be associated with the upregulation of MMPs.

Keywords: adriamycin; apoptosis; astragalosides; cytoskeleton; migration; oxidative stress; podocyte.

Figure 1.

Comparison of podocyte survival rates between the groups. Values are expressed as the mean ± standard deviation (n=3). **P<0.01 vs. the control group; ^#P<0.05, ^##P<0.01 vs. the podocyte injury group. ASTL/M/H, treatment with low/medium/high concentration of astragaloside.

Figure 2.

Comparison of the podocyte migration rate between the groups. Values are expressed as the mean ± standard deviation (n=3). **P<0.01 vs. the control group; ^##P<0.01 vs. the podocyte injury group. ASTL/M/H, treatment with low/medium/high concentration of astragaloside.

Figure 3.

Migration of podocytes in different groups. Images of crystal violet-stained cells on the lower side of the Transwell assay membranes are presented (magnification, ×200). (A) Control group; (B) podocyte injury group; (C) ASTL group; (D) ASTM group; (E) ASTH group. ASTL/M/H, treatment with low/medium/high concentration of astragaloside.

Figure 4.

Cytoskeletal and nuclear staining of injured podocytes in different groups (magnification, ×400). (A) Control group; (B) podocyte injury group; (C) ASTL group; (D) ASTM group; (E) ASTH group. ASTL/M/H, treatment with low/medium/high concentration of astragaloside; FITC, fluorescein isothiocyanate.