Effects of mechanical stimulation on the biomechanics and histology of stem cell-collagen sponge constructs for rabbit patellar tendon repair
Effects of mechanical stimulation on the biomechanics and histology of stem cell-collagen sponge constructs for rabbit patellar tendon repair
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DOI：
10.1089/ten.2006.12.2291
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发表时间：
2006-08-01
影响因子：
--
通讯作者：
Butler, David L.
中科院分区：
文献类型：
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作者：
Juncosa-Melvin, Natalia;Shearn, Jason T.;Butler, David L.
本研究的目的是确定机械刺激如何影响干细胞-胶原海绵构建体用于修复兔髌骨中央肌腱缺损的生物力学和组织学。通过将来自10只成年兔子的间充质干细胞以0.14 x 10(6)个细胞/次的速度植入I型胶原海绵中，构建了用于体外和体内分析的自体组织工程构建体。其中一半的构建体每5分钟机械刺激一次，持续8小时/天，达到峰值应变4%，持续2周。另一半在无机械刺激的培养箱中待2周。分配给体外测试的样本显示，机械刺激构建体的线性刚度是非刺激构建体的2.5倍。用于体内研究的其余配对结构被植入兔髌骨肌腱中央三分之一的双侧全厚度、全长缺陷中。术后12周，对修复组织进行生物力学（7对）和组织学（3对）分析。刺激（与非刺激）修复的最大力、线刚度、最大应力和线模量平均为正常髌腱中央三分之一对应值的70%（与55%相比）、85%（与55%相比）、70%（与50%相比）和50%（与40%相比）。机械刺激修复的平均力-伸长曲线也与正常髌骨肌腱的相应曲线相匹配，高达先前研究中记录的体内峰值力值的150%。结构和修复线性刚度和线性模量也呈正相关（r分别= 0.6和0.7）。组织学上，两种修复都显示出良好的细胞排列和轻度的装饰素和V型胶原染色，中度的纤维连接蛋白和III型胶原染色。这项研究表明，干细胞-胶原蛋白海绵结构的机械刺激可以显著改善肌腱修复的生物力学，达到并远远超过体内负荷的功能极限。
The objective of this study was to determine how mechanical stimulation affects the biomechanics and histology of stem cell-collagen sponge constructs used to repair central rabbit patellar tendon defects. Autogenous tissue-engineered constructs were created for both in vitro and in vivo analyses by seeding mesenchymal stem cells from 10 adult rabbits at 0.14 x 10(6) cells/construct in type I collagen sponges. Half of these constructs were mechanically stimulated once every 5 min for 8 h/day to a peak strain of 4% for 2 weeks. The other half remained in an incubator without mechanical stimulation for 2 weeks. Samples allocated for in vitro testing revealed that mechanically stimulated constructs had 2.5 times the linear stiffness of nonstimulated constructs. The remaining paired constructs for in vivo studies were implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Twelve weeks after surgery, repair tissues were assigned for biomechanical (7 pairs) and histologic (3 pairs) analyses. Maximum force, linear stiffness, maximum stress, and linear modulus for the stimulated (vs. nonstimulated) repairs averaged 70% (vs. 55%), 85% (vs. 55%), 70% (vs. 50%), and 50% (vs. 40%) of corresponding values for the normal central third of the patellar tendons. The average force-elongation curve for the mechanically stimulated repairs also matched the corresponding curve for the normal patellar tendons, up to 150 % of the peak in vivo force values recorded in a previous study. Construct and repair linear stiffness and linear modulus were also positively correlated (r = 0.6 and 0.7, respectively). Histologically both repairs showed excellent cellular alignment and mild staining for decorin and collagen type V, and moderate staining for fibronectin and collagen type III. This study shows that mechanical stimulation of stem cell-collagen sponge constructs can significantly improve tendon repair biomechanics up to and well beyond the functional limits of in vivo loading.