Kosnik P E, Faulkner J A, Dennis R G
Department of Biomedical Engineering and Institute of Gerontology, University of Michigan, Ann Arbor, Michigan 48109-2007, USA.
Tissue Eng. 2001 Oct;7(5):573-84. doi: 10.1089/107632701753213192.
A myooid is a three-dimensional skeletal muscle construct cultured from mammalian myoblasts and fibroblasts. The purpose was to compare over several weeks in culture the morphology, excitability, and contractility of myooids developed from neonatal and adult rat cells. The hypotheses tested were as follows: (1) baseline forces of myooids correlate with the cross-sectional area (CSA) of the myooids composed of fibroblasts, and (2) peak isometric tetanic forces normalized by total CSA (specific P(o)) of neonatal and adult rat myooids are not different. Electrical field stimulation was used to measure the excitability and peak tetanic forces. The proportion of the CSA composed of fibroblasts was greater for neonatal (40%) than adult (17%) myooids. For all myooids the baseline passive force normalized by fibroblast CSA (mean = 5.5 kPa) correlated with the fibroblast CSA (r(2) = 0.74). A two-element cylindrical model was analyzed to determine the contributions of fibroblasts and myotubes to the baseline force. At each measurement period, the specific P(o) of the adult myooids was greater than that of the neonatal myooids. The specific P(o) of the adult myooids was approximately 1% of the control value for adult muscles and did not change with time in culture, while that of neonatal myooids increased.
肌样体是一种由哺乳动物成肌细胞和成纤维细胞培养而成的三维骨骼肌结构。目的是在数周的培养过程中比较由新生大鼠和成年大鼠细胞发育而来的肌样体的形态、兴奋性和收缩性。所检验的假设如下：（1）肌样体的基线力与由成纤维细胞组成的肌样体的横截面积（CSA）相关，以及（2）新生大鼠和成年大鼠肌样体经总CSA标准化后的等长强直收缩峰值力（特定P(o)）没有差异。使用电场刺激来测量兴奋性和强直收缩峰值力。新生肌样体（40%）中由成纤维细胞组成的CSA比例高于成年肌样体（17%）。对于所有肌样体，经成纤维细胞CSA标准化后的基线被动力（平均值 = 5.5 kPa）与成纤维细胞CSA相关（r(2) = 0.74）。分析了一个二元圆柱形模型以确定成纤维细胞和肌管对基线力的贡献。在每个测量期，成年肌样体的特定P(o)大于新生肌样体的特定P(o)。成年肌样体的特定P(o)约为成年肌肉对照值的1%，并且在培养过程中不随时间变化，而新生肌样体的特定P(o)则增加。
