Kobayashi Yohei, Saita Yoshitomo, Takaku Tomoiku, Yokomizo Tomomasa, Nishio Hirofumi, Ikeda Hiroshi, Takazawa Yuji, Nagao Masashi, Kaneko Kazuo, Komatsu Norio
Department of Orthopaedics, Juntendo University Faculty of Medicine, Tokyo, Japan.
Department of Hematology, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
J Exp Orthop. 2020 Jul 8;7(1):49. doi: 10.1186/s40634-020-00267-1.
Although platelet-rich plasma (PRP) therapy has become an increasingly popular treatment for sports-related injuries, the molecular mechanisms of PRP on tissue healing process remain poorly understood. The aim of the present study was to develop an experimental method quantifying the efficacy of PRP with murine patellar tendon injury model, leading to future elucidation of the mechanisms of PRP on healing processes.
Full-thickness defects were created in the central third of the murine patellar tendon. The prepared allogenic PRP gel was applied on the defect of the patellar tendon (PRP group), while the remaining mice served as the untreated control group. Mice were sacrificed at 2, 4, 6, 8, and 10 weeks after the operation, with histological sections obtained in each time point (n = 4 / time point / group). Semi-quantitative histological evaluation was performed in accordance with the Bonar score. The variables included in this scoring system were cell morphology, ground substance, collagen arrangement, and vascularity, with higher grades indicating worse tendon structures. In addition, the ratio of the collagen fibers to the entire tendon tissue (FT ratio) was measured using KS400 software as a quantitative histological evaluation.
The total Bonar score in the PRP group was significantly lower than in control group. With regard to the variables in the Bonar score, the vascularity score was significantly higher in the PRP group at 2 and 4 weeks, while the collagen arrangement score was significantly lower in the PRP group at 8 weeks. Based on a quantitative evaluation, the recovery speed of the patellar tendon determined by FT ratio was significantly faster in the PRP group than in the control group at 6 and 8 weeks.
We have developed an experimental method for histological and quantitative evaluation of the effects of PRP on tissue healing using murine patellar tendon injury model. The results of this study suggest that the local application of PRP could enhance the tissue-healing process both directly through action on localized cells and indirectly through the recruitment of reparative cells through the blood flow. Further investigations will be needed to confirm the mechanisms of PRP in tissue-healing processes with the development of this experimental model.
尽管富血小板血浆（PRP）疗法已成为治疗运动相关损伤越来越常用的方法，但PRP对组织愈合过程的分子机制仍知之甚少。本研究的目的是建立一种实验方法，利用小鼠髌腱损伤模型量化PRP的疗效，以便未来阐明PRP对愈合过程的作用机制。
在小鼠髌腱中部三分之一处制造全层缺损。将制备好的同种异体PRP凝胶应用于髌腱缺损处（PRP组），其余小鼠作为未治疗的对照组。术后2、4、6、8和10周处死小鼠，在每个时间点获取组织学切片（每组每个时间点n = 4）。根据博纳尔评分进行半定量组织学评估。该评分系统纳入的变量包括细胞形态、基质、胶原排列和血管形成，分数越高表明肌腱结构越差。此外，使用KS400软件测量胶原纤维与整个肌腱组织的比例（FT比例），作为定量组织学评估。
PRP组的总博纳尔评分显著低于对照组。关于博纳尔评分中的变量，PRP组在2周和4周时血管形成评分显著更高，而在8周时PRP组的胶原排列评分显著更低。基于定量评估，在6周和8周时，PRP组通过FT比例确定的髌腱恢复速度显著快于对照组。
我们建立了一种利用小鼠髌腱损伤模型对PRP对组织愈合的影响进行组织学和定量评估的实验方法。本研究结果表明，局部应用PRP可直接通过作用于局部细胞以及间接通过血流募集修复细胞来增强组织愈合过程。随着该实验模型的发展，还需要进一步研究来证实PRP在组织愈合过程中的作用机制。
