Hybrid Scaffolds Composed of Amino-Acid Coated Sponge and Hydroxyapatite for Hard Tissue Formation by Bone Marrow Cells

Takayoshi Yabuuchi,Hiroyuki Hayashi,Masataka Yoshikawa,Hideyuki Kakigi

doi:10.4236/jbise.2014.76034

Abstract

A formalin-treated polyvinyl-alcohol (PVF) sponge is convenient as a scaffold because its configuration is easily modified. However, coating the sponge with an adhesive chemical agent is necessary to attach bone marrow cells (BMCs) to the sponge structure. Moreover, it was considered that a hybrid scaffold composed of a sponge and enveloped cylindrical porous hydroxyapatite (HA) would be convenient. In this study, the effect of leucine (Leu) coating on a PVF sponge was examined for osteogenesis on an HA/PVF hybrid scaffold by rat BMCs (rBMCs). In an in vivo assessment, the sponge immersed in Leu solution (10 mg/ml) was inserted into the hollow center of cylindrical HA. The sponge received 1.5 × 106 rBMCs obtained from male Fischer 344 rats. The hybrid scaffolds were then implanted subcutaneously of syngeneic rats for 6 weeks. In vitro assessment of Leu to hard tissue formation with coating on the well or addition in rBMC culture medium was also performed in a 6-well plate for 2 weeks. In vivo examinations showed the excellent effect of Leu coating on PVF sponge. Leu-coated PVF sponge in the scaffolds showed marked new bone formation in the pores by histological examination. Leu-coated PVF sponge showed a high quantity of osteocalcine (OC). HA might prevent the release of rBMCs from PVF as a barrier. In in vitro examinations, the quantity of OC in rBMC culture with and without the addition of Leu in culture medium showed no significant difference. However, addition of Leu showed significant ALP activity level in culture medium. Leu coating in culture plate wells showed no influence on the quantity of OC. It was concluded from the results that Leu might prevent the emigration of rBMCs to the outside of the scaffold and promote the differentiation of cells to osteoblasts in the scaffold.

Highlights

Regeneration of hard tissue is an ideal method to restore partial tooth defects or to replace a missing tooth
A small number of rat BMCs (rBMCs) emigrated from the sponge into the surrounding HA structure of the hybrid scaffold
It was concluded in this study that Leu plays an important role in the sponge component of the hybrid scaffold for bone formation by coating the fine structure

Summary

Introduction

Regeneration of hard tissue is an ideal method to restore partial tooth defects or to replace a missing tooth. The potential of induced pluripotent stem cells (iPS cells) is extremely high for the regeneration of tissue or organs. Tooth regeneration by iPS cells should be studied in dentistry [1] [2]. As it is well known, teeth have a specific structure consisting of ectoderm and mesodermal tissue and show a complex configuration. On the right and left sides of the maxilla and mandible, anterior teeth, canines, premolars and molars vary in configuration, respectively. Teeth reveal an individual indigenous complicated configuration. It is considered that tooth regeneration by iPS cells may not be realized immediately

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