Yan Ruijian, Gu Yanjia, Ran Jisheng, Hu Yejun, Zheng Zefeng, Zeng Mengfeng, Heng Boon Chin, Chen Xiao, Yin Zi, Chen Weishan, Shen Weiliang, Ouyang Hongwei
Department of Orthopedic Surgery, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Dr Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, School of Medicine, Zhejiang University, Hangzhou, China.
Am J Sports Med. 2017 Jul;45(8):1909-1920. doi: 10.1177/0363546517694357. Epub 2017 Mar 16.
Chronic tendinopathy is a commonly occurring clinical problem that affects both athletes and inactive middle-aged patients. Although some studies have shown that different platelet-rich plasma (PRP) preparations could exert various therapeutic effects in vitro, the role of leukocytes in PRP has not yet been defined under tendinopathy conditions in vivo.
This study compared the effects of the intratendon delivery of leukocyte-poor PRP (Lp-PRP) versus leukocyte-rich PRP (Lr-PRP) in a rabbit chronic tendinopathy model in vivo.
Controlled laboratory study.
Four weeks after a local injection of collagenase in the Achilles tendon, the following treatments were randomly administered on the lesions: injections of (1) 200 μL of Lp-PRP (n = 8), (2) 200 μL of Lr-PRP (n = 8), or (3) 200 μL of saline (n = 8). Healing outcomes were assessed at 4 weeks after therapy with magnetic resonance imaging (MRI), cytokine quantification, real-time polymerase chain reaction analysis of gene expression, histology, and transmission electron microscopy (TEM).
MRI revealed that the Lr-PRP and saline groups displayed higher signal intensities compared with the Lp-PRP group with T2 mapping. Histologically, the Lp-PRP group displayed significantly better general scores compared with the Lr-PRP ( P = .001) and saline ( P < .001) groups. Additionally, TEM showed that the Lp-PRP group had larger collagen fibril diameters than the Lr-PRP group ( P < .001). Enzyme-linked immunosorbent assay showed a significantly lower level of catabolic cytokine IL-6 in the Lp-PRP group compared with the Lr-PRP ( P = .001) and saline ( P = .021) groups. The Lp-PRP group displayed significantly increased expression of collagen I compared with the saline group ( P = .004) but not the Lr-PRP group. Both the Lp-PRP and Lr-PRP groups exhibited significantly lower matrix metalloproteinase (MMP)-1 and MMP-3 expression levels compared with the saline group. However, only the Lp-PRP group displayed significantly higher expression of TIMP-1 than the saline group ( P = .024).
Compared with Lr-PRP, Lp-PRP improves tendon healing and is a preferable option for the clinical treatment of tendinopathy.
PRP is widely used in the clinical management of chronic tendinopathy. However, the clinical results are ambiguous. It is imperative to understand the influence of leukocytes on PRP-mediated tissue healing in vivo, which could facilitate the better clinical management of chronic tendinopathy. Further studies are needed to translate our findings to the clinical setting.
慢性肌腱病是一种常见的临床问题，影响运动员和不活动的中年患者。尽管一些研究表明，不同的富血小板血浆（PRP）制剂在体外可发挥多种治疗作用，但在体内肌腱病条件下，PRP中白细胞的作用尚未明确。
本研究在兔慢性肌腱病模型中，比较了体内肌腱内注射贫白细胞PRP（Lp-PRP）与富白细胞PRP（Lr-PRP）的效果。
对照实验室研究。
在跟腱局部注射胶原酶4周后，对损伤部位随机给予以下治疗：（1）注射200μL Lp-PRP（n = 8），（2）注射200μL Lr-PRP（n = 8），或（3）注射200μL生理盐水（n = 8）。在治疗后4周，通过磁共振成像（MRI）、细胞因子定量、基因表达的实时聚合酶链反应分析、组织学和透射电子显微镜（TEM）评估愈合结果。
MRI显示，在T2映射中，Lr-PRP组和生理盐水组的信号强度高于Lp-PRP组。组织学上，Lp-PRP组的总体评分显著优于Lr-PRP组（P = .001）和生理盐水组（P < .001）。此外，TEM显示，Lp-PRP组的胶原纤维直径大于Lr-PRP组（P < .001）。酶联免疫吸附测定显示，Lp-PRP组的分解代谢细胞因子IL-6水平显著低于Lr-PRP组（P = .001）和生理盐水组（P = .021）。与生理盐水组相比，Lp-PRP组的I型胶原表达显著增加（P = .004），但与Lr-PRP组相比无显著差异。与生理盐水组相比，Lp-PRP组和Lr-PRP组的基质金属蛋白酶（MMP）-1和MMP-3表达水平均显著降低。然而，只有Lp-PRP组的TIMP-1表达显著高于生理盐水组（P = .024）。
与Lr-PRP相比，Lp-PRP可改善肌腱愈合，是肌腱病临床治疗的更佳选择。
PRP广泛应用于慢性肌腱病的临床治疗。然而，临床结果尚不明确。必须了解白细胞对体内PRP介导的组织愈合的影响，这有助于更好地临床管理慢性肌腱病。需要进一步研究将我们的发现转化到临床环境中。
