The Study of the Frequency Effect of Dynamic Compressive Loading on Primary Articular Chondrocyte Functions Using a Microcell Culture System

Abstract

Compressive stimulation can modulate articular chondrocyte functions. Nevertheless, the relevant studies are not comprehensive. This is primarily due to the lack of cell culture apparatuses capable of conducting the experiments in a high throughput, precise, and cost-effective manner. To address the issue, we demonstrated the use of a perfusion microcell culture system to investigate the stimulating frequency (0.5, 1.0, and 2.0 Hz) effect of compressive loading (20% and 40% strain) on the functions of articular chondrocytes. The system mainly integrates the functions of continuous culture medium perfusion and the generation of pneumatically-driven compressive stimulation in a high-throughput micro cell culture system. Results showed that the compressive stimulations explored did not have a significant impact on chondrocyte viability and proliferation. However, the metabolic activity of chondrocytes was significantly affected by the stimulating frequency at the higher compressive strain of 40% (2 Hz, 40% strain). Under the two compressive strains studied, the glycosaminoglycans (GAGs) synthesis was upregulated when the stimulating frequency was set at 1 Hz and 2 Hz. However, the stimulating frequencies explored had no influence on the collagen production. The results of this study provide useful fundamental insights that will be helpful for cartilage tissue engineering and cartilage rehabilitation.

A Guide for Using Mechanical Stimulation to Enhance Tissue-Engineered Articular Cartilage Properties

“…72 In addition, chondrocytes in monolayer stimulated with 20% compressive strain at 2 Hz exhibited an estimated 45% upregulation of GAG production. 36 These studies along with others shown in Table 1 confirm the benefits that DC stimulation has on GAG content in AC constructs. 8,11 Shear AC experiences shear stresses during normal physiological movement and loading.…”

“…In static cultures, chondrocytes in the inner region of AC constructs have limited access to signals and nutrients causing them to lose function and their chondrocytic phenotype. 36 Cell viability and proliferation are measured using metabolic assays, and cellular content may be measured indirectly by quantifying DNA content. TEAC is biomimetic and employable for translation only if it houses viable chondrocytes with high proliferative potential and AC-specific ECM production.…”

Differential effect of frequency and duration of mechanical loading on fetal chick cartilage and bone development

“…Active fetal movements such as whole-body movements, kicking, and stretching subject the developing skeleton to stresses, strains and hydrostatic pressure. Animal studies have shown that limiting fetal movements by inhibiting or immobilising muscle activity leads to altered activity of developmental regulatory genes and skeletal abnormalities such as reduced rudiment length and bone formation, distorted spinal curvature, and abnormal joint cavitation and morphogenesis, highlighting the importance of these forces for normal development (Brunt et al, 2015;Kahn et al, 2009;Levillain et al, 2019;Nowlan et al, 2010a;Nowlan et al, 2010b;Roddy et al, 2011;Rolfe et al, 2013;Sotiriou et al, 2019).…”

“…introduction Healthy skeletal development depends on physiological ranges of biomechanical stimuli, evident by the range of musculoskeletal conditions associated with reduced fetal movement reported in clinical cases and in in vivo animal immobilisation models (reviewed in Nowlan, 2015). However, the understanding of how type and quantity of mechanical stimulation directs cartilage and bone www.ecmjournal.org N Khatib et al…”

A mathematical model of tissue-engineered cartilage development under cyclic compressive loading

“…In order to increase the production of extracelular matrix and mechanical properties of the cultured tissues, mechanical stimulation in bioreactors has provided good results. Various experimental studies in bioreactors have shown that the application of cyclic unconfined compression at moderate strains (2-15%) and frequencies (0.01-3Hz) stimulates the production of collagen and proteoglycans and increases the mechanical properties of the constructs (Lee and Bader 1997;Hung et al 2004;Kisiday et al 2004;Tsuang et al 2008;Lin et al 2014). Computational modeling techniques are useful to establish protocols for mechanical stimulationof tissueengineered cartilage, as well as to provide further insights on outputs not easily measurable experimentally.…”