Efficacy for Whitlockite for Augmenting Spinal Fusion.

Su Yeon Kwon,Chang Su Lim,Jung Hee Shim,Yu Ha Kim,Inbo Han,Seong Bae An

doi:10.3390/ijms222312875

Su Yeon Kwon, Chang Su Lim + Show 4 more

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https://doi.org/10.3390/ijms222312875

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Abstract

Whitlockite (WH) is the second most abundant inorganic component of human bone, accounting for approximately 25% of bone tissue. This study investigated the role of WH in bone remodeling and formation in a mouse spinal fusion model. Specifically, morphology and composition analysis, tests of porosity and surface area, thermogravimetric analysis, an ion-release test, and a cell viability test were conducted to analyze the properties of bone substitutes. The MagOss group received WH, Group A received 100% beta-tricalcium phosphate (β-TCP), Group B received 100% hydroxyapatite (HAp), Group C received 30% HAp/70% β-TCP, and Group D received 60% HAp/40% β-TCP (n = 10 each). All mice were sacrificed 6 weeks after implantation, and micro-CT, hematoxylin and eosin (HE) staining, and Masson trichome (MT) staining and immunohistochemistry were performed. The MagOss group showed more homogeneous and smaller grains, and nanopores (<500 nm) were found in only the MagOss group. On micro-CT, the MagOss group showed larger fusion mass and better graft incorporation into the decorticate mouse spine than other groups. In the in vivo experiment with HE staining, the MagOss group showed the highest new bone area (mean: decortication group, 9.50%; A, 15.08%; B, 15.70%; C, 14.76%; D, 14.70%; MagOss, 22.69%; p < 0.0001). In MT staining, the MagOss group demonstrated the highest new bone area (mean: decortication group, 15.62%; A, 21.41%; B, 22.86%; C, 23.07%; D, 22.47%; MagOss, 26.29%; p < 0.0001). In an immunohistochemical analysis for osteocalcin, osteopontin, and CD31, the MagOss group showed a higher positive area than other groups. WH showed comparable bone conductivity to HAp and β-TCP and increased new bone formation. WH is likely to be used as an improved bone substitute with better bone conductivity than HAp and β-TCP.

Highlights

This study investigated the role of WH in bone remodeling and formation in spinal fusion in mice through an interdisciplinary approach to evaluate the effect of this new bone substitute material
The scanning electron microscopy (SEM) observations confirmed the results for the morphology of granules and macropores at lower magnification (Figure 1)
The grain size of the MagOss group was approximately 300 nm, but the grain size of Groups A and B ranged from 500 nm to 2 μm and that of Groups C and D was more than 1 μm

Summary

Introduction

On micro-CT, the MagOss group showed larger fusion mass and better graft incorporation into the decorticate mouse spine than other groups. In the in vivo experiment with HE staining, the MagOss group showed the highest new bone area (mean: decortication group, 9.50%; A, 15.08%; B, 15.70%; C, 14.76%; D, 14.70%; MagOss, 22.69%; p < 0.0001). In MT staining, the MagOss group demonstrated the highest new bone area (mean: decortication group, 15.62%; A, 21.41%; B, 22.86%; C, 23.07%; D, 22.47%; MagOss, 26.29%; p < 0.0001). WH showed comparable bone conductivity to HAp and β-TCP and increased new bone formation. Autologous bone graft is the gold-standard material for bone fusion, because it has characteristics necessary for new bone formation, such as osteoconductivity, osteoinductivity, and osteogenicity [4,5,6,7].

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