Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Tokyo, Japan.
Platelets. 2021 Apr 3;32(3):413-419. doi: 10.1080/09537104.2020.1754382. Epub 2020 Apr 18.
Platelet-rich fibrin (PRF) is prepared from whole blood without any exogenous coagulation factors. Several preparation methods have now been introduced, particularly with differences in centrifugation parameters including g-force and time to improve their regenerative potential. Nevertheless, the centrifugation systems have not yet been clearly investigated for their influences on the PRF clot properties. The aim of the present study was to visually and histologically characterize the cell separation manner and blood cell localization on the whole PRF clots prepared by two different centrifugation system, fixed-angle and horizontal centrifugation. Leukocyte- and platelet-rich fibrin (L-PRF) was prepared on a fixed-angle centrifuge machine (IntraSpin, Intra-Lock, FL, USA) at 2700 rpm (~400 g at the RCF-clot; ~700 g at the RCF-max) for 12 min. The PRF prepared by horizontal centrifugation was prepared on a horizontal centrifugation (H-PRF) (Eppendorf 5702, Eppendorf, Germany) at 700 g at the RCF-max for 8 min. The cell morphology and localization were observed on the surface of PRF clots by scanning electron microscopy (SEM) and histologically by transaxial frozen sections by means of a film method. L-PRF clots demonstrated a sloped separation between the upper plasma and the bottom red blood cell (RBC) layers according to the angle of the rotor. Red dots were often observed on the distal walls of the tubes in the upper layers, consisting of aggregations of RBCs, leukocytes and platelets by SEM and histology. Clots produced on the horizontal centrifuge showed much smoother cell layer distribution/separation along the tube surfaces when compared to L-PRF. Horizontal centrifugation also demonstrated more evenly distributed platelets throughout the PRF clots when compared to L-PRF that gathered the majority of cells along the distal tube surface or within the buffy-coat region. In summary, it was found that horizontal centrifugation resulted in a more uniform blood cell separation of PRF clots when compared to the accumulation of cells gathered along the distal tube surfaces produced prepared by fixed-angle centrifugation. Future research is needed to evaluate the benefit of horizontal centrifugation in clinical practice.
富血小板纤维蛋白 (PRF) 是从不含任何外源性凝血因子的全血中制备的。现在已经引入了几种制备方法，特别是在离心参数方面，包括离心力和时间，以提高其再生潜力。然而，对于这些离心系统对 PRF 凝块特性的影响，尚未进行明确的研究。本研究的目的是通过两种不同的离心系统（定角和水平离心）制备的整个 PRF 凝块的直观和组织学特征来描述细胞分离方式和血细胞定位。白细胞和富血小板纤维蛋白 (L-PRF) 在定角离心机 (IntraSpin，Intra-Lock，FL，USA) 上以 2700 rpm(约 400g 在 RCF-凝块；约 700g 在 RCF-max) 离心 12min 制备。通过水平离心制备的 PRF 在水平离心机 (H-PRF)(Eppendorf 5702，Eppendorf，德国) 上以 700g 在 RCF-max 离心 8min 制备。通过扫描电子显微镜 (SEM) 在 PRF 凝块表面观察细胞形态和定位，并通过薄膜法的横切冷冻切片进行组织学观察。L-PRF 凝块根据转子的角度在上血浆层和下红细胞 (RBC) 层之间呈现出倾斜的分离。在管的上层的远端壁上经常观察到红色斑点，SEM 和组织学分析表明这些红色斑点由 RBC、白细胞和血小板聚集而成。与 L-PRF 相比，在水平离心机上制备的凝块在管表面上显示出更平滑的细胞层分布/分离。与 L-PRF 相比，水平离心还显示出 PRF 凝块中血小板分布更加均匀，L-PRF 中大部分细胞聚集在管的远端表面或在缓冲层区域。总之，与固定角离心制备的沿着管远端表面聚集的细胞相比，水平离心导致 PRF 凝块中血细胞分离更加均匀。需要进一步的研究来评估水平离心在临床实践中的益处。
