Oral Biol Res 2018; 42(3): 105-113  https://doi.org/10.21851/obr.42.03.201809.105
Hydroxyapatite coated magnesium alloy for peripheral nerve regeneration
Akram Abdo Almansoori1,2,3, Kyung Won Ju2, Bongju Kim2,3, Soung Min Kim1,3, Sung-Mi Lee4, Jong-Ho Lee1,2,3,5*
1Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, Korea 
2Clinical Translational Research Center for Dental Science, Seoul National University Dental Hospital, Seoul, Korea 
3Dental Research Institute, Seoul National University, Seoul, Korea  
4Department of Material Science and Engineering, College of Engineering, Seoul National University, Seoul, Korea 
5Oral Cancer Center, Seoul National University Dental Hospital, Seoul, Korea
Correspondence to: Jong-Ho Lee, Department of Oral and Maxillofacial Surgery and Clinical Trial Center and Oral Cancer Center, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.
Tel: +82-2-2072-2630, Fax: +82-2-766-4948, E-mail: leejongh@snu.ac.kr
Received: June 20, 2018; Revised: June 25, 2018; Accepted: June 26, 2018; Published online: September 30, 2018.
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Magnesium (Mg) has been used as a neuroprotective agent and for orthopedic and cardiovascular stent applications for a long time. Mg is a promising material for neural regeneration own to its metallic nature, biodegradability, and biocompatibility. To evaluate the beneἀt of hydroxyapatite (HA) coated Mg alloy (WE43) nerve conduit in peripheral nerve injury regeneration. In vitro cell adhesion and proliferation of PC12 cells and Schwann cells over pure Mg, WE43, HA coated pure Mg (HA-Mg), and HA coated WE43 (HA-WE43) disks were assessed using scanning electron microscope and EZ-CYTOX assay. In vivo study was also performed for sham, silicone nerve conduits, and HA-WE43 nerve conduits to evaluate rat sciatic nerve regeneration over 10 mm gap. Ḁese rats were observed for three months with weekly functional assessment using sciatic functional index. Regeneration was evaluated through retrograde neuron labeling and histomorphometric analysis at the end of the experiment. Non-coated pure Mg and WE43 conduits showed fast resorption rate and high gas formation. Higher adhesion and proliferation of PC12 cells were found in HA-WE43 disks. At the end of three months, HA-WE43 nerve conduit showed mild resorption without detectable gas formation in the surrounding tissue. However, only scanty regenerated neural tissue was found within the conduit. HA-WE43 nerve conduit showed controlled degradation and absence of gas formation with scanty regenerated neural tissue. 
Keywords: Hydroxyapatite, Magnesium, Nerve conduit, Peripheral nerve regeneration

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