Efficacy of electrical polarization on a rat femoral bone defect model with a custom-made external fixator

Article type: Research Article

Authors: Ohara, Masato^a | Itoh, Soichiro^b | Fujiwara, Hiroyoshi^a; | Oda, Ryo^a | Tsuchida, Shinji^a | Kohata, Kazuhiro^c | Yamashita, Kimihiro^{b; c} | Kubo, Toshikazu^a

Affiliations: [a] Department of Orthopedics, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, Japan | [b] Strategic Innovation Research Hub, Laboratory of Strength of Material and Science, Teikyo University, Itabashi-ku, Tokyo, Japan | [c] Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Chiyoda, Tokyo, Japan

Correspondence: [*] Corresponding author: Hiroyoshi Fujiwara, Department of Orthopedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan. Tel.: +81 75 251 5549; Fax: +81 75 251 5841; E-mail: fjwr@koto.kpu-m.ac.jp

Abstract: BACKGROUND:We have developed a technology to electrically polarize living bone. OBJECTIVE:The effects of stored electrical charge in electrical polarized bone on the facilitation of new bone formation were assayed. METHODS:Stimulated depolarized current measurement was performed in electrically polarized and nonpolarized femora of SD rats. These bone specimens were implanted into bone defects of the rat femora and fixed with a custom-made external fixator. X-ray imaging of the implant was performed every week. After 3 weeks, micro-CT scanning was performed to evaluate the displacement rate. Histological observation was performed, and the occupancy ratio of the newly formed bone was calculated from tissue specimens stained with Villanueva’s Goldner method. RESULTS:There was a tendency for the displacement rate of the implant to be smaller and the occupancy ratio of the newly formed bone to be larger, especially at the distal end, in the polarized group compared with the nonpolarized group. The time of callus appearance was significantly earlier in the polarized group than in the nonpolarized group, and bridging callus grew from the distal to the proximal end. CONCLUSIONS:Bone specimens can be electrically polarized, and the stored electrical charge can work effectively to facilitate new bone formation.

Keywords: Electrical polarization, electrical charge, living bone, rat femoral bone defect model, external fixator

DOI: 10.3233/BME-191068

Journal: Bio-Medical Materials and Engineering, vol. 30, no. 5-6, pp. 475-486, 2019