Department of Orthopaedic Surgery, Thompson Laboratory for Regenerative Orthopaedics, University of Missouri, Columbia, Missouri, USA.
Am J Sports Med. 2021 Jan;49(1):215-225. doi: 10.1177/0363546520971852. Epub 2020 Dec 1.
Different tendons are chosen for anterior cruciate ligament (ACL) reconstruction based on perceived advantages and disadvantages, yet there is a relative paucity of information regarding biologic responsiveness of commonly used tendon grafts to mechanical strain.
To evaluate the in vitro responses of graft fibroblasts derived from tendons used for ACL reconstruction to clinically relevant strain levels.
Controlled laboratory study.
Twelve quadriceps tendons (QTs), 12 patellar tendons (PTs), and 9 hamstring tendons (HTs) were harvested from skeletally mature dogs (n = 16). Tendon fibroblasts were isolated and seeded onto BioFlex plates (1 × 10 cells/well). Cells were subjected to 3 strain conditions (stress deprivation, 0%; physiologic, 4%; high, 10%) for 5 days. Media were collected for proinflammatory and metabolic assays. RNA was extracted for gene expression analysis using real-time reverse transcription polymerase chain reaction.
Stress deprivation elicited significantly higher metabolic activity from HT and PT cells than from QT cells ( < .001 and = .001, respectively). There were no differences in metabolic activity among all 3 graft fibroblasts at physiologic and high strain. COL-1 expression was significantly higher in PT versus HT during physiologic strain ( = .007). No significant differences with COL-3 expression were seen. TIMP-1 ( = .01) expression was higher in PT versus HT under physiologic strain. Scleraxis expression was higher in PT versus HT ( = .007) under physiologic strain. A strain-dependent increase in PGE2 levels occurred for all grafts. At physiologic strain conditions, HT produced significantly higher levels of PGE2 versus QT ( < .001) and PT ( = .005).
Fibroblasts from common ACL graft tissues exhibited different metabolic responses to mechanical strain. On the basis of these data, we conclude that early production of extracellular matrix and proinflammatory responses from ACL grafts are dependent on mechanical loading and graft source.
Graft-specific differences in ACL reconstruction outcomes are known to exist. Our results suggest that there are differences in the biologic responsiveness of cells from the tendon grafts used in ACL reconstruction, which are dependent on strain levels and graft source. The biologic properties of the tissue used for ACL reconstruction should be considered when selecting graft source.
基于对优缺点的认识，不同的肌腱被用于前交叉韧带（ACL）重建，但关于常用肌腱移植物对机械应变的生物学反应的信息相对较少。
评估源自用于 ACL 重建的肌腱的移植物成纤维细胞对临床相关应变水平的体外反应。
对照实验室研究。
从骨骼成熟的狗中采集 12 个股四头肌肌腱（QT）、12 个髌腱（PT）和 9 个腘绳肌腱（HT）（n = 16）。分离肌腱成纤维细胞并接种于 BioFlex 板上（1×10 个细胞/孔）。细胞接受 3 种应变条件（无应激，0%；生理，4%；高，10%）处理 5 天。收集培养基进行促炎和代谢检测。用实时逆转录聚合酶链反应提取 RNA 进行基因表达分析。
无应激条件下 HT 和 PT 细胞的代谢活性显著高于 QT 细胞（<.001 和 =.001）。在生理和高应变条件下，所有 3 种移植物成纤维细胞的代谢活性均无差异。在生理应变时，PT 中的 COL-1 表达显著高于 HT（ =.007）。COL-3 表达未见明显差异。生理应变时，PT 中的 TIMP-1 表达（ =.01）高于 HT。生理应变时，PT 中的 Scleraxis 表达高于 HT（ =.007）。所有移植物的 PGE2 水平均随应变增加而增加。在生理应变条件下，HT 产生的 PGE2 水平明显高于 QT（<.001）和 PT（ =.005）。
源自常见 ACL 移植物组织的成纤维细胞对机械应变表现出不同的代谢反应。基于这些数据，我们得出结论，ACL 移植物的细胞早期产生细胞外基质和促炎反应取决于机械加载和移植物来源。在选择移植物来源时，应考虑 ACL 重建中使用的组织的生物学特性。
已知 ACL 重建结果存在移植物特异性差异。我们的结果表明，ACL 重建中使用的肌腱移植物细胞的生物学反应存在差异，这些差异取决于应变水平和移植物来源。在选择移植物来源时，应考虑 ACL 重建中使用的组织的生物学特性。
