Exploring protective effect of Glycine tabacina aqueous extract against nephrotic syndrome by network pharmacology and experimental verification

Abstract

Background: Glycine tabacina (Labill.) Benth, one of the traditional Chinese herbal medicines, has been used for treatment of nephritis, osteoporosis, rheumatism, and menopausal syndrome. The aim of this study was to illuminate the therapeutic effect and mechanism of Glycine tabacina aqueous extract (GATE) in the treatment of nephrotic syndrome (NS).

Methods: UHPLC-DAD-MS/MS was used to analyze the chemical profile of GATE. Adriamycin (ADR)-induced NS mouse model and network pharmacology methods were conducted to explore the protective effect and mechanism of GATE on NS treatment.

Results: GATE administration significantly ameliorated symptoms of proteinuria and hyperlipidemia in NS mice, as evidenced by reduced excretion of urine protein and albumin, and decreased plasma levels of total cholesterol and triglyceride. Decreased blood urea nitrogen (BUN) and creatinine levels in NS mice suggested that GATE could prevent renal function decline caused by ADR. GATE treatment also inhibited ADR-induced pathological lesions of renal tissues as indicated by periodic acid Schiff staining. Six flavonoids of GATE were identified by using UHPLC-DAD-MS/MS. Network pharmacology analysis indicated that the protection of GATE in treating NS might be associated with the regulation of oxidative stress and inflammation. In addition, the in vivo experiment validated that treatment with GATE markedly decreased reactive oxygen species production, malonaldehyde level, and increased superoxide dismutase activity both in plasma and renal tissues. TNF-α level in plasma and protein expression in kidney were significantly decreased in GATE treatment groups.

Conclusions: Combination of network pharmacology analysis and experimental verification revealed that GATE exerts anti-NS effect possibly through modulating oxidative stress and inflammation, suggesting the potential application of GATE or its derivatives in the prevention and treatment of NS and other related kidney diseases.

Keywords: Glycine tabacina aqueous extract; Inflammation; Nephrotic syndrome; Network pharmacology; Oxidative stress.

Fig. 1

Scheme of the study

Fig. 2

Effect of GATE on proteinuria in ADR-induced NS mice. Mice were orally administrated with GATE (2.5 and 5 g raw herb/kg body weight) or benazepril (5 mg/kg) once daily starting from day 0. Control and model group were given an equal volume of water. a Body weight was observed twice a week. b Relative kidney weight was determined at the end of the experiment. The excretion of 24-h urine protein (c) and urine albumin (d) was measured on day 0, 4, 7, 11, 18 and 25. The data were expressed as means ± SEM. *p < 0.05, **p < 0.01 compared with control group; ^#p < 0.05, ^##p < 0.01 compared with model group

Fig. 3

Effect of GATE on renal function, hyperlipidemia and renal histopathological changes in ADR-induced NS mice. Blood was collected on day 0, 7, 14 and 25 after ADR injection. Then plasma levels of BUN (a), creatinine (b), total cholesterol (c) and triglyceride (d) were determined using the corresponding assay kits. The data were expressed as means ± SEM. *p < 0.05, **p < 0.01 compared with control group; ^#p < 0.05, ^##p < 0.01 compared with model group. At the end of experiment, mice were sacrificed and the right kidney was removed for histological analysis (e)

Fig. 4

UHPLC-UV chromatogram (a) and total ion chromatogram (b) of GATE. The compounds were identified as genistin (1), daidzin (2), isoschaftoside (3), daidzein (4), glycitein (5), genistein (6), respectively

Fig. 5

PPI network (a) and KEGG enrichment analysis (b) of GATE targets against NS. a Nodes in the network indicate proteins, where edges refer to the protein–protein interactions. The size and different colors of the circle represent to the degree. Number of nodes: 92; number of edges: 589; average degree: 12.8. b The y-axis of bubble map shows significantly KEGG pathways of the overlapping targets, and the x-axis is the GeneRatio. The higher GeneRatio indicates the more targets belonging to a specific pathway. Size of spot indicates the counts of targets and color reflects the different adjusted p value

Fig. 6

A “GATE-targets-pathways-NS” network built by Cytoscape 3.7.2. In the network, ellipse, quadrangle and triangle nodes represent targets, chemical components and pathways, respectively. While edges stand for the interactions among chemical components of GATE, NS, targets and pathways

Fig. 7

Effect of GATE on oxidative stress and TNF-α expression in ADR-induced NS mice. At the end of experiment, blood and left kidneys of mice from different groups were collected. Then plasma SOD activity (a) and MDA level (b), renal tissue SOD activity (c), MDA level (d) and ROS level (e) were measured using the corresponding assay kits. f Representative Western blots of TNF-α expression in kidney tissues from different groups on day 25. g The plasma TNF-α level of mice in each group was determined by ELISA on day 25. The data were expressed as means ± SEM. *p < 0.05, **p < 0.01 compared with control group; ^#p < 0.05, ^##p < 0.01 compared with model group