The effects of varying frequency and duration of mechanical stimulation on a tissue-engineered tendon construct
The effects of varying frequency and duration of mechanical stimulation on a tissue-engineered tendon construct
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DOI：
10.1080/03008207.2017.1324431
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发表时间：
2018-01-01
影响因子：
2.9
通讯作者：
Sikavitsas, Vassilios I.
中科院分区：
文献类型：
--
作者：
Engebretson, Brandon;Mussett, Zachary R.;Sikavitsas, Vassilios I.
脱细胞的、废弃的人体组织，如人的脐静脉，已被广泛用于组织工程应用，包括肌腱移植。当细胞再分化时，这种天然支架在3D动态培养环境(生物反应器系统)中培养。对于肌腱组织工程移植物，这样的系统通常采用单轴拉伸应变形式的振荡机械刺激。这种刺激的三个主要参数是频率、持续时间和力度。在这项研究中，我们研究了改变刺激时间(0.5、1和2小时/天)和频率(0.5、1、2周期/分钟)对种植于间充质干细胞培养长达7天的人脐静脉的影响。构建物的应变保持在2%恒定。0.5h/d、1个周期/min的细胞增殖率最高(203%)，其次为1h/d、1个周期/min(增加170%)。静态培养以及2个周期/分钟的频率和2小时/天的拉伸持续时间并不能显著促进细胞增殖。细胞外基质的质量和构筑纤维的排列与细胞密度有直接关系，细胞密度最高的组改善最大。基因表达表明细胞活动与肌腱样组织重塑一致。此外，某些组在7天后硬化轴、Tenascin-C和Tenomodrin上调，成骨细胞、软骨细胞和脂肪细胞表型受到抑制。本研究考察的刺激参数表明，在早期培养中，较低的频率和较短的持续时间对构建质量最好。
Decellularized, discarded human tissues, such as the human umbilical vein, have been widely utilized for tissue engineering applications, including tendon grafts. When recellularized, such natural scaffolds are cultured in 3D dynamic culture environments (bioreactor systems). For tendon tissue-engineered grafts, such systems often employ oscillatory mechanical stimulation in the form uniaxial tensile strain. The three main parameters of such stimulation are frequency, duration, and force. In this study we investigated the effects of changing the duration (0.5, 1, and 2 h/day) and frequency (0.5, 1, 2 cycles/min) of stimulation of a human umbilical vein seeded with mesenchymal stem cells cultured for up to 7 days. Strain of the construct was held constant at 2%. The highest proliferation rates were observed in the 0.5 h/day duration and 1 cycle/min frequency (203% increase) with a close second being 1 h/day and 1 cycle/min frequency (170% increase). Static cultures along with a 2 cycles/min frequency and a 2 h/day duration of stretching did not increase cellular proliferation significantly. Extracellular matrix quality and alignment of the construct fibers had a direct relation to cellularity and those groups with the highest cellularity improved the most. Gene expression indicated cellular activity consistent with tendon-like tissue remodeling. In addition, scleraxis, tenascin-C, and tenomodulin were upregulated in certain groups after 7 days, with osteoblast, chondrocyte, and adipocyte phenotypes depressed. The stimulation parameters investigated in this study indicated that slower frequencies and shorter durations were best for construct quality in early stage cultures.