Biomechanical Effects of Kaempferol Treatments on the Bone Healing Process of Murine Tibia

Kaempferol is a typical flavonol-type flavonoid and has a protective effect on postmenopausal bone loss, and previous studies have reported that kaempferol treated groups show an increase in the callus size and bone mineral density as well as improvement in biomechanical behaviors in comparison with untreated control groups in the bone healing process. The present study aims at investigating the effect of kaempferol treatments on fractured murine tibia, by measuring kaempferol dose-dependent mechanical properties in the bone healing process of murine tibia fracture models. A stabilized fracture was generated at tibia by minor modification of the Hiltunen method for 8 weeks old ICR mice weighting 29.0 ∼ 30.5 g. Experimental mice were divided into 4 groups. Kaempferol of 0.2, 1.0, 5.0 mg/kg (body weight) with 20 % ethanol was administered to 3 groups and the remaining one group was only treated with 20 % ethanol as a control group. Three-point bending fracture tests were conducted to measure the mechanical properties (fracture load, fracture energy, stiffness) of murine tibiae at non-fractured regions near fracture sites 21 days after kaempferol treatments, via a custom-made biomechanical testing system (BTS, KST Co., Korea). The 5.0 mg/kg kaempferol treated group shows higher fracture load (20.54 ±5.04 N) than the control group (17.82 ±5.94 N). Fracture energy, total energy applied to tibia up to bone fracture, exhibited no significant differences between the control group and any of the kampferol treated groups, although both the 1.0 mg/kg kaempferol treated and control groups showed a little higher fracture energy than the 0.2 and 5.0 mg/kg kaempferol treated groups. Bone stiffness also did not show statistically significant differences between the control group and any of the kaempferol treated groups, with the highest stiffness value observed in the 1.0 mg/kg kaempferol treated group.