Dau Michael, Ganz Cornelia, Zaage Franziska, Frerich Bernhard, Gerber Thomas
Department of Oral, Maxillofacial and Plastic Surgery, University Medical Center Rostock, Rostock, Germany.
Institute of Physics, Rostock University, Rostock, Germany.
Int J Nanomedicine. 2017 Oct 12;12:7393-7404. doi: 10.2147/IJN.S142550. eCollection 2017.
The aim of this study was to examine the in vivo characteristics and levels of integration and degradation of a ready-to-use bone grafting block with elastic properties (elastic block) for the use in surgery.
Thirty-six male Wistar rats underwent surgical creation of a well-defined bone defect in the tibia. All created defects - one per animal - were filled with an unsintered nanocrystalline hydroxyapatite embedded either with a non-cross-linked hydrogel carrier (CONT, n=18) or a cross-linked hydrogel carrier (elastic block [EB], n=18) based on polyvinylpyrrolidone (PVP) and silica sol, respectively. The animals were killed after 12 (n=12), 21 (n=12) and 63 days (n=12). The bone formation and defect healing were quantified by histomorphometric measurements made in paraffin sections. Additionally, immunohistochemical (tartrate-resistant acid phosphatase [TRAP] and alkaline phosphatase [aP]), antibody-based examinations (CD68) and energy-dispersive x-ray scattering measurements of silica atom concentration were carried out.
A larger remaining bone defect area overall was observed in EB after 12 days and 21 days. After 63 days, similar areas of remaining bone defects were found. The amount of the remaining carrier material in EB overall was higher at all times. In CONT no residual carrier material was found at 12 days and later. CD68 analyses showed significantly lower level of CD68-positive marked cells after 21 days in CONT, and nonsignificant differences at 12 and 63 days, respectively. Additionally, a significantly higher level of aP-positive marked cells was observed in CONT after 12 days. Later on, the levels of aP-positive marked cells were slightly higher in EB (21 and 63 days). Furthermore, no significant differences regarding the level of TRAP-positive marked cells in each group were observed.
The bone substitute (EB) with the cross-linked PVP-based hydrogel carrier leads at the beginning to a higher amount of remaining carrier material and remaining bone substitute. This delayed degradation is supposed to be the reason for the observed lower level of bone remodeling and is caused by the irradiation changes (cross links) in the structure in PVP.
本研究旨在检测一种具有弹性特性的即用型骨移植块（弹性块）在手术中使用时的体内特性、整合水平和降解情况。
36只雄性Wistar大鼠接受手术，在胫骨上制造明确的骨缺损。所有制造的缺损（每只动物一个）分别用嵌入非交联水凝胶载体（对照组，n = 18）或交联水凝胶载体（弹性块[EB]，n = 18）的未烧结纳米晶羟基磷灰石填充，所述水凝胶载体分别基于聚乙烯吡咯烷酮（PVP）和硅溶胶。在12天（n = 12）、21天（n = 12）和63天（n = 12）后处死动物。通过在石蜡切片上进行组织形态计量学测量来量化骨形成和缺损愈合情况。此外，还进行了免疫组织化学（抗酒石酸酸性磷酸酶[TRAP]和碱性磷酸酶[aP]）、基于抗体的检查（CD68）以及硅原子浓度的能量色散X射线散射测量。
在12天和21天后，总体上在EB组观察到更大的剩余骨缺损面积。63天后，发现剩余骨缺损面积相似。在所有时间点，EB组中剩余载体材料的总量总体上更高。在对照组中，12天及之后未发现残留载体材料。CD68分析显示，在21天后对照组中CD68阳性标记细胞水平显著降低，在12天和63天时分别无显著差异。此外，在12天后对照组中观察到aP阳性标记细胞水平显著更高。之后，在EB组中aP阳性标记细胞水平在21天和63天时略高。此外，每组中TRAP阳性标记细胞水平未观察到显著差异。
具有交联PVP基水凝胶载体的骨替代物（EB）在开始时导致更高量的剩余载体材料和剩余骨替代物。这种降解延迟被认为是观察到的骨重塑水平较低的原因，并且是由PVP结构中的辐射变化（交联）引起的。
