Zhang Lei, Chen Shuo, Chang Peng, Bao Nirong, Yang Chao, Ti Yufan, Zhou Liwu, Zhao Jianning
Department of Orthopedics, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China.
Department of Plastic and Reconstructive Surgery, General Hospital of Shenyang Military Area Command, Shenyang, China.
Am J Sports Med. 2016 Aug;44(8):1941-51. doi: 10.1177/0363546516644718. Epub 2016 May 16.
Platelet-rich plasma (PRP) is now widely used as a promising treatment for patients with tendinopathy. However, the efficacy of PRP treatment for tendinopathy is controversial mainly because of inconsistent results from human clinical trials and particularly because the concentration and effect of leukocytes in PRP remain largely unknown.
Leukocyte-rich PRP (L-PRP) inhibits growth factor release, decreases proliferation, and induces nontenocyte differentiation of tendon stem cells (TSCs); increases catabolic cytokine concentrations; and causes inflammation and apoptosis. Thus, L-PRP has a detrimental effect on tendon stem/progenitor cells, which impairs injured tendon healing.
Controlled laboratory study.
Pure PRP (P-PRP) and L-PRP were prepared from the same individual rabbit blood, and platelet numbers in each PRP product were adjusted to reach the same level. The leukocyte level in L-PRP was 4 and 8 times higher than those in whole blood and P-PRP, respectively. The growth factors in both P-PRP and L-PRP were measured by enzyme-linked immunosorbent assay kits. The morphology, stemness, proliferation, and differentiation of TSCs grown in L-PRP and P-PRP were examined by microscopy, immunocytochemistry, population doubling time, quantitative real-time polymerase chain reaction, and histological analysis.
L-PRP produced lower levels of growth factors, such as vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), transforming growth factor (TGF)-β1, and platelet-derived growth factor (PDGF), than did P-PRP. TSC proliferation was significantly decreased in L-PRP in a concentration-dependent manner. Furthermore, TSCs cultured in P-PRP produced more collagen and formed tendon-like tissue; however, TSCs grown in L-PRP differentiated into nontenocytes and produced more inflammatory factors such as membrane-associated prostaglandin synthase (mPGES) and interleukin (IL)-1β. Moreover, L-PRP was associated with increased apoptosis.
L-PRP has harmful effects on TSCs.
This study revealed the direct effects of different compositions of PRP on TSCs and provided basic scientific data to help understand the cellular and molecular mechanisms of the efficacy of PRP treatment in clinical use.
富血小板血浆（PRP）目前作为一种有前景的治疗方法被广泛应用于肌腱病患者。然而，PRP治疗肌腱病的疗效存在争议，主要是因为人体临床试验结果不一致，尤其是PRP中白细胞的浓度和作用在很大程度上仍不清楚。
富含白细胞的PRP（L-PRP）抑制生长因子释放，降低增殖，并诱导肌腱干细胞（TSCs）的非肌腱细胞分化；增加分解代谢细胞因子浓度；并导致炎症和细胞凋亡。因此，L-PRP对肌腱干/祖细胞有有害作用，这会损害受损肌腱的愈合。
对照实验室研究。
从同一只兔子的血液中制备纯PRP（P-PRP）和L-PRP，并将每种PRP产品中的血小板数量调整到相同水平。L-PRP中的白细胞水平分别比全血和P-PRP中的白细胞水平高4倍和8倍。通过酶联免疫吸附测定试剂盒测量P-PRP和L-PRP中的生长因子。通过显微镜检查、免疫细胞化学、群体倍增时间、定量实时聚合酶链反应和组织学分析，检测在L-PRP和P-PRP中生长的TSCs的形态、干性、增殖和分化。
与P-PRP相比，L-PRP产生的血管内皮生长因子（VEGF）、表皮生长因子（EGF）、转化生长因子（TGF）-β1和血小板衍生生长因子（PDGF）等生长因子水平较低。L-PRP中TSC增殖以浓度依赖性方式显著降低。此外，在P-PRP中培养的TSCs产生更多胶原蛋白并形成肌腱样组织；然而，在L-PRP中生长的TSCs分化为非肌腱细胞并产生更多炎症因子，如膜相关前列腺素合酶（mPGES）和白细胞介素（IL）-1β。此外，L-PRP与细胞凋亡增加有关。
L-PRP对TSCs有有害作用。
本研究揭示了PRP不同成分对TSCs的直接影响，并提供了基础科学数据，以帮助理解PRP治疗在临床应用中的疗效的细胞和分子机制。
