Molecular mechanisms of Buqing granule for the treatment of diabetic retinopathy: Network pharmacology analysis and experimental validation

Figure 1 Research flow chart. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001.

Figure 2 Prediction of diabetic retinopathy components and targets of action of Buqing granule therapy. A: Main ingredients of Buqing granule (BQKL); B: BQKL-active ingredients-targets of action diagram (The rhombus, square hexagon, and square represent the herbal medicine, active ingredient, and target site, respectively); C: Venn diagram of BQKL and diabetic retinopathy (DR) intersection targets; D: Protein-ptrotein interaction network map and screened core BQKL targets for DR treatment (The darker the color, the larger the icon, the higher the degree value). TSZ: Tusizi; GQZ: Gouqizi; DGP: Digupi; CQZ: Cheqianzi; GJH: Ganjuhua; SDH: Shudihuang; BFL: Baifuling; DR: Diabetic retinopathy; BQKL: Buqing granule.

Figure 3 Gene ontology and the Kyoto encyclopedia of genes and genomes enrichment analyses. A: Gene ontology enrichment analysis; B: Kyoto encyclopedia of genes and genomes enrichment analysis; C: Core genes enriched in the MAPK signaling pathway.

Figure 4 Molecular docking.

Figure 5 Changes in body weight and blood sugar at different time points. A: Body weight at different time points; B: Blood glucose at different time points. The sequence from left to right represents the control group, the model group, the BQKL group and the CaD group. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. BQKL: Buqing granule; CaD: Calcium dobesilate.

Figure 6 Serum biochemical analyses and ELISA tests. A: Effect of Buqing granule (BQKL) on total cholesterol and triglyceride levels in the serum of diabetic retinopathy (DR) rats; B: Effect of BQKL on superoxide dismutase, malondialdehyde, and glutathione peroxidase contents in the retina of DR rats; C: Effect of BQKL on oxidative stress in rat serum. The sequence from left to right represents the control group, the model group, the BQKL group and the Calcium dobesilate group. ^aP < 0.05, ^cP < 0.001. BQKL: Buqing granule; CaD: Calcium dobesilate.

Figure 7 Effects of Buqing granule on retinal morphology in diabetic retinopathy rats. A: Hematoxylin & eosin staining of the retina of rats in each group (400 ×); B: Retinal ganglion cell count in each group; C: Comparison of retinal thickness in each group. The sequence from left to right represents the control group, the model group, the Buqing granule group and the Calcium dobesilate group. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. BQKL: Buqing granule; CaD: Calcium dobesilate. GCL: Ganglion cell layer; IPL: Inner plexiform layer; INL: Inner nuclear layer; OPL: Outer plexiform layer; ONL: Outer nuclear layer.

Figure 8 Immunohistochemical results of retinal tissue from different rat models. A: Immunohistochemical detection of Caspase-3; B: Immunohistochemical detection of c-Jun; C: Immunohistochemical detection of MAPK1; D: Immunohistochemical detection of MAPK3 positive expression (200 ×). The sequence from left to right represents the control group, the model group, the Buqing granule group and the calcium dobesilate group. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. BQKL: Buqing granule; CaD: Calcium dobesilate.

Figure 9 A molecular biological perspective on the role of Buqing granule in the diabetic retinopathy treatment. A: Caspase-3, AKT1, c-Jun, TP53, MAPK1, and MAPK3 mRNA expression levels determined by real-time quantitative reverse transcription-PCR; B: Protein expression levels determined by western blotting. The sequence from left to right represents the control group, the model group, the Buqing granule group and the calcium dobesilate group. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. BQKL: Buqing granule; CaD: Calcium dobesilate.

Figure 10  Graphical abstract.