Background:

Tendinopathy is still a great challenge in clinical practice, and the role of platelet-rich plasma (PRP) is controversial. The influence of leukocytes on tendinopathy at an early stage has not been defined so far.

Purpose:

To compare the effects of leukocyte-rich PRP (Lr-PRP) and leukocyte-poor PRP (Lp-PRP) on Achilles tendinopathy when applied at an early stage.

Study Design:

Controlled laboratory study.

Methods:

A rabbit Achilles tendinopathy model was induced by a collagenase injection. A week later, treatments were applied randomly on local Achilles tendon lesions: (1) 200 μL of Lr-PRP (16 legs), (2) 200 μL of Lp-PRP (16 legs), and (3) 200 μL of saline (16 legs). At 3 and 6 weeks after the collagenase injection, outcomes were evaluated by histology, magnetic resonance imaging (MRI), real-time polymerase chain reaction analysis, immunohistochemistry, and transmission electron microscopy (TEM).

Results:

The Lr-PRP group had a lower T2 signal intensity (P = .0377) and smaller diameter (P = .0193) and cross-sectional area (P = .0194) than the Lp-PRP group on MRI. Histologically, the Lr-PRP group had better scores than the Lp-PRP group (P = .0284 and P = .0188, respectively). Compared with the Lp-PRP group, higher gene expression and more protein synthesis of collagen I (P = .0160 and P = .0309, respectively) and CD163 (P < .0001 and P = .0411, respectively) were found in the Lr-PRP group. Considering TEM and biomechanical testing, the Lr-PRP group demonstrated more mature collagen fibers (P < .0001), a larger fiber diameter (P = .0005), a higher failure load (P = .00417), and higher tensile stress (P < .0001) than the Lp-PRP group.

Conclusion:

Lr-PRP had more beneficial effects than Lp-PRP when delivered at an early stage during tendon repair.

Clinical Relevance:

Here, we showed that tendinopathy influenced the curative effects of PRP in vivo. An early-stage application of Lr-PRP had more benefits for the repair of tendinopathy than Lp-PRP in a rabbit model, which will supplement guidelines of PRP treatment on tendinopathy clinically.

中文翻译：

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在兔模型中，早期跟腱炎病中富含白细胞的血小板丰富血浆和富含白细胞的血小板贫血血浆的比较。

背景：

肌腱病在临床实践中仍然是一个巨大的挑战，富血小板血浆（PRP）的作用引起争议。到目前为止，尚未确定白细胞对肌腱病的早期影响。

目的：

比较早期使用富含白细胞的PRP（Lr-PRP）和贫白细胞的PRP（Lp-PRP）对跟腱病的影响。

学习规划：

对照实验室研究。

方法：

通过胶原酶注射诱导家兔跟腱病模型。一周后，随机对局部跟腱损伤进行了治疗：（1）200μLLr-PRP（16条腿），（2）200μLLp-PRP（16条腿）和（3）200μL生理盐水（16条腿）。胶原酶注射后3周和6周，通过组织学，磁共振成像（MRI），实时聚合酶链反应分析，免疫组织化学和透射电子显微镜（TEM）评估结局。

结果：

与MRI上的Lp-PRP组相比，Lr-PRP组的T2信号强度较低（P = .0377），直径较小（P = .0193）和横截面积（P = .0194）。从组织学上讲，Lr-PRP组的得分高于Lp-PRP组（分别为P = .0284和P = .0188）。与Lp-PRP组相比，胶原蛋白I（分别为P = .0160和P = .0309）和CD163（分别为P <.0001和P = .0411）具有更高的基因表达和更多的蛋白质合成。Lr-PRP组。考虑到TEM和生物力学测试，Lr-PRP组显示出更成熟的胶原纤维（P<.0001），与Lp-PRP组相比，更大的纤维直径（P = .0005），更高的破坏载荷（P = .00417）和更高的拉应力（P <.0001）。

结论：

在肌腱修复的早期阶段，Lr-PRP比Lp-PRP具有更有益的作用。

临床相关性：

在这里，我们表明肌腱病影响了体内PRP的疗效。在兔模型中，Lr-PRP的早期应用比Lp-PRP对肌腱病的修复有更多益处，这将在临床上补充PRP治疗肌腱病的指南。