Formononetin, an active compound of Astragalus membranaceus (Fisch) Bunge, inhibits hypoxia-induced retinal neovascularization via the HIF-1α/VEGF signaling pathway

Figures & data

Figure 1 Structure of 7-hydroxy-4′-methoxyisoflavone (FMN).

Figure 2 The effects of FMN on VEGF secretion in the ARPE-19 cells at 48 hours under hypoxic condition.

Notes: The results are representative of at least three independent experiments run in triplicate and expressed as mean ± SD. **P<0.01 vs CoCl₂-treated group. The control cells were treated with a culture medium containing 0.1% DMSO.
Abbreviations: FMN, formononetin; ARPE-19, acute retinal pigment epithelial-19; SD, standard deviation; DMSO, dimethyl sulfoxide.

Figure 3 The effects of FMN on the mRNA expressions of VEGFA (A), HIF-1α (B), and PHD-2 (C) in the ARPE-19 cells at 24 hours under normoxia or hypoxic condition.

Notes: The results are representative of at least three independent experiments run in triplicate and expressed as mean ± SD. **P<0.01 vs CoCl₂-treated cells. The control cells were treated with a culture medium containing 0.1% DMSO.
Abbreviations: FMN, formononetin; ARPE-19, acute retinal pigment epithelial-19; SD, standard deviation; DMSO, dimethyl sulfoxide.

Figure 4 The effects of FMN on the protein expressions of HIF-1α (A) and PHD-2 (B) in the ARPE-19 cells at 24 hours under normoxia or hypoxic condition.

Notes: The results are representative of at least three independent experiments run in triplicate and expressed as mean ± SD. *P<0.05, **P<0.01 vs CoCl₂-treated cells. The control cells were treated with a culture medium containing 0.1% DMSO.
Abbreviations: FMN, formononetin; ARPE-19, acute retinal pigment epithelial-19; SD, standard deviation; DMSO, dimethyl sulfoxide.

Figure 5 The effects of FMN on quantification of preretinal neovascular area ratio in the OIR rats.

Notes: (A) Retinal NV area ration. (B) Inhibition of retinal neovascular area. The results were expressed as mean ± SD (n=10). *P<0.05, **P<0.01, compared to the OIR rats.
Abbreviations: FMN, formononetin; OIR, oxygen-induced retinopathy; NV, neovascularization; SD, standard deviation; CBC, conbercept ophthalmic injection.

Figure 6 The effects of Conbercept and FMN on retinal NV of the OIR rats in the ADPase-stained retinal sections (40×).

Notes: Central retinal region (A1–E1) and peripheral retinal region (A2–E2) of rat pups fostered under normoxia conditions (control), and OIR rats under 80% oxygen. The rats were treated with normal saline (control), 1.0 mg/kg Conbercept, and 5.0 mg/kg or 10.0 mg/kg FMN by ip injection. Ten rats were used for each group. The red arrowhead shows the vessel tortuosity, and dilated vessels.
Abbreviations: FMN, formononetin; NV, neovascularization; OIR, oxygen-induced retinopathy; ADP, adenosine diphosphate; ip, intraperitoneal.

Figure 7 The effects of FMN on retinal NV in H&E-stained retinal tissue sections (×400).

Notes: (A) Control group, rat pups fostered under normoxia conditions, (B) treated with normal saline (C) treated with 1.0 mg/kg Conbercept, (D) treated with 10.0 mg/kg FMN OIR rats under 80% oxygen. The rats were treated with normal saline (control), 1.0 mg/kg Conbercept, or 10.0 mg/kg FMN by ip injection. Ten rats were used for each group. Red arrows indicate neovascular nuclei or vessel.
Abbreviations: FMN, formononetin; NV, neovascularization; H&E, hematoxylin and eosin; OIR, oxygen-induced retinopathy; ip, intraperitoneal.

Figure 8 FMN alleviates hypoxia-induced retinal angiogenesis through suppression of the HIF-1α/VEGF signaling pathway.

Abbreviations: FMN, formononetin; NV, neovascularization.