Formononetin promotes early fracture healing through stimulating angiogenesis by up-regulating VEGFR-2/Flk-1 in a rat fracture model

• Published in: International immunopharmacology Vol. 9; no. 12; pp. 1357 - 1365
• Main Authors: Huh, Jeong-Eun, Kwon, Na-Hyun, Baek, Young-Hyun, Lee, Jae-Dong, Choi, Do-Young, Jingushi, Seiya, Kim, Kang-il, Park, Dong-Suk
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.11.2009; Elsevier
• Subjects: Animals; Astragalus membranaceus; Biological and medical sciences; Bone healing; Bony Callus - blood supply; Bony Callus - drug effects; Bony Callus - metabolism; Bony Callus - pathology; Cell Differentiation - drug effects; Cell Differentiation - physiology; Chondrogenesis - drug effects; Chondrogenesis - physiology; Collagen Type I - biosynthesis; Collagen Type I - genetics; Disease Models, Animal; Femur - blood supply; Femur - drug effects; Femur - injuries; Femur - pathology; Formononetin; Fractures, Bone - drug therapy; Fractures, Bone - pathology; Fractures, Bone - physiopathology; Isoflavones - administration & dosage; Isoflavones - chemistry; Male; Medical sciences; Mesenchymal Stromal Cells - drug effects; Mesenchymal Stromal Cells - pathology; Neovascularization, Physiologic - drug effects; Neovascularization, Physiologic - physiology; Osteocalcin - biosynthesis; Osteocalcin - genetics; Osteogenesis; Osteopontin - biosynthesis; Osteopontin - genetics; Pharmacology. Drug treatments; Phytoestrogens - administration & dosage; Phytoestrogens - chemistry; Phytotherapy; Plant Extracts - administration & dosage; Plant Roots; Rats; Rats, Sprague-Dawley; Receptors, Vascular Endothelial Growth Factor - genetics; Receptors, Vascular Endothelial Growth Factor - metabolism; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; VEGF; VEGF receptor; Wound Healing - drug effects; VEGF receptor; Bone healing; Formononetin; VEGF; Osteogenesis; Animal model; Rat; Diseases of the osteoarticular system; Fracture; Osteoarticular system; Angiogenesis; Healing agent; Neovascularization; Vascular endothelial growth factor receptor 2; Cicatrization; Biological receptor; Vascular endothelial growth factor receptor 1; Rodentia; Trauma; Fetal liver kinase 1; Vertebrata; Mammalia; Vascular endothelium growth factor; Early; Bone
• ISSN: 1567-5769; 1878-1705; 1878-1705
• DOI: 10.1016/j.intimp.2009.08.003

Plant-derived phytoestrogens have bone protective effects, but the molecular mechanism behind these effects remains unclear. This study is aimed at fully characterizing the fracture healing process of formononetin, and investigating the mechanism underlying angiogenesis in calluses of a rat fracture model. Femoral fractures were produced in 2-month-old Sprague–Dawley rats. A 20 µg/kg or 200 µg/kg dose of formononetin was orally administrated once a day during the healing period of 21 days. The results showed that in the early stage of chondrogenesis (days 3), formononetin significantly increased the number of vessels, and expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR-2/flk-1) compared with control. However, the larger dose of formononetin had no significant difference on expression of VEGF and VEGFR-2/Flk-1 compared with that of the smaller dose of formononetin. After 7 days of administration, formononetin markedly induced differentiation of mesenchymal stem cells in the fracture site. After 14 days, gene expression of mesenchymal progenitors such as alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN) and collagen type I (Col I), indicating osteogenic differentiation, was markedly stimulated by formononetin compared with control. These results suggest that formononetin promotes early fracture healing through angiogenesis activation in the early stage of fracture repair, and osteogenesis acceleration in the later stages, and thus may be beneficial for fracture healing.