Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 200092, China.
Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 200092, China; School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China.
Med Eng Phys. 2024 Jul;129:104189. doi: 10.1016/j.medengphy.2024.104189. Epub 2024 May 25.
Understanding the role of mechanical force on tissue nutrient transport is essential, as sustained force may affect nutrient levels within the disc and initiate disc degeneration. This study aims to evaluate the time-dependent effects of different compressive force amplitudes as well as tensile force on glucose concentration and cell viability within the disc. Based on the mechano-electrochemical mixture theory, a multiphasic finite element model of the lumbar intervertebral disc was developed. The minimum glucose concentration and minimum cell density in both normal and degenerated discs were predicted for different compressive force amplitudes, tensile force, and corresponding creep time. Under high compressive force, the minimum glucose concentration exhibited an increasing and then decreasing trend with creep time in the normal disc, whereas that of the degenerated disc increased, then decreased, and finally increased again. At steady state, a higher compressive force was accompanied by a lower glucose concentration distribution. In the degenerated disc, the minimum cell density was negatively correlated with creep time, with a greater range of affected tissue under a higher compressive force. For tensile force, the minimum glucose concentration of the degenerated disc raised over time. This study highlighted the importance of creep time, force magnitude, and force type in affecting nutrient concentration and cell viability. Sustained weight-bearing activities could deteriorate the nutrient environment of the degenerated disc, while tensile force might have a nonnegligible role in effectively improving nutrient levels within the degenerated disc.
理解机械力对组织营养物质运输的作用至关重要，因为持续的力可能会影响椎间盘内的营养水平并引发椎间盘退变。本研究旨在评估不同压缩力幅值以及拉伸力对椎间盘内葡萄糖浓度和细胞活力的时变影响。基于力电化学混合理论，建立了腰椎间盘的多相有限元模型。预测了不同压缩力幅值、拉伸力及其相应的蠕变时间下正常和退变椎间盘的最小葡萄糖浓度和最小细胞密度。在高压缩力下，正常椎间盘的最小葡萄糖浓度随蠕变时间呈先增加后减少的趋势，而退变椎间盘的最小葡萄糖浓度则先减少后增加。在稳态下，较高的压缩力伴随着较低的葡萄糖浓度分布。在退变椎间盘，最小细胞密度与蠕变时间呈负相关，较大的压缩力作用范围影响更大的组织。对于拉伸力，退变椎间盘的最小葡萄糖浓度随时间增加。本研究强调了蠕变时间、力大小和力类型对影响营养浓度和细胞活力的重要性。持续的负重活动可能会恶化退变椎间盘的营养环境，而拉伸力可能在有效提高退变椎间盘内的营养水平方面发挥不可忽视的作用。
