Galbusera Fabio, Mietsch Antje, Schmidt Hendrik, Wilke Hans-Joachim, Neidlinger-Wilke Cornelia
Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, D-89081, Ulm, Germany.
Comput Methods Biomech Biomed Engin. 2013;16(3):328-37. doi: 10.1080/10255842.2011.619184. Epub 2011 Oct 4.
Degeneration of the intervertebral disc may be initiated and supported by impairment of the nutrition processes of the disc cells. The effects of degenerative changes on cell nutrition are, however, only partially understood. In this work, a finite volume model was used to investigate the effect of endplate calcification, water loss, reduction of disc height and cyclic mechanical loading on the sustainability of the disc cell population. Oxygen, lactate and glucose diffusion, production and consumption were modelled with non-linear coupled partial differential equations. Oxygen and glucose consumption and lactate production were expressed as a function of local oxygen concentration, pH and cell density. The cell viability criteria were based on local glucose concentration and pH. Considering a disc with normal water content, cell death was initiated in the centre of the nucleus for oxygen, glucose, and lactate diffusivities in the cartilaginous endplate below 20% of the physiological values. The initial cell population could not be sustained even in the non-calcified endplates when a reduction of diffusion inside the disc due to water loss was modelled. Alterations in the disc shape such as height loss, which shortens the transport route between the nutrient sources and the cells, and cyclic mechanical loads, could enhance cell nutrition processes.
椎间盘退变可能由椎间盘细胞营养过程受损引发并持续。然而，退变变化对细胞营养的影响仅得到部分理解。在这项研究中，使用有限体积模型来研究终板钙化、水分流失、椎间盘高度降低和循环机械负荷对椎间盘细胞群体可持续性的影响。氧气、乳酸和葡萄糖的扩散、生成和消耗通过非线性耦合偏微分方程进行建模。氧气和葡萄糖的消耗以及乳酸的生成表示为局部氧气浓度、pH值和细胞密度的函数。细胞活力标准基于局部葡萄糖浓度和pH值。对于含水量正常的椎间盘，当软骨终板中氧气、葡萄糖和乳酸的扩散系数低于生理值的20%时，细胞核中心开始出现细胞死亡。当模拟由于水分流失导致椎间盘内部扩散减少时，即使在未钙化的终板中，初始细胞群体也无法维持。椎间盘形状的改变，如高度降低（这缩短了营养源与细胞之间的运输路径）以及循环机械负荷，可增强细胞营养过程。
