Effects of medium perfusion rate on cell-seeded three-dimensional bone constructs in vitro

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• Static culture of tissue-engineered constructs suffers from limited nutrient and waste transport, reducing cellular activity in construct centers.
• Perfusion systems offer a potential solution to overcome these transport limitations in three-dimensional (3D) cellular constructs.

Purpose of the Study:

• To investigate the impact of varying medium perfusion rates on cell viability, proliferation, and gene expression in 3D bone scaffolds.
• To determine optimal flow conditions for MC3T3-E1 osteoblast-like cells cultured within human trabecular bone scaffolds.

Main Methods:

• Human trabecular bone scaffolds were seeded with MC3T3-E1 cells and cultured under perfusion for one week at rates of 0.01, 0.1, 0.2, and 1.0 mL/min.
• Cell viability was assessed using confocal microscopy.
• Cell proliferation was quantified via DNA analysis.
• Gene expression (Runx2, osteocalcin, alkaline phosphatase) was analyzed using real-time RT-PCR.

Main Results:

• High perfusion (1.0 mL/min) led to significant cell death, while lower rates improved cell viability, especially in the construct center.
• Cell proliferation increased at a flow rate of 0.01 mL/min compared to 0.2 mL/min and static controls.
• Osteogenic gene expression (Runx2, osteocalcin, alkaline phosphatase) was upregulated at 0.2 mL/min relative to lower flow rates.

Conclusions:

• Medium perfusion can enhance nutrient and waste transport in 3D bone scaffolds, benefiting cell development in vitro.
• Flow-mediated mechanical stimuli may also contribute to improved tissue development.
• Optimizing perfusion rate is critical for balancing cell viability, proliferation, and differentiation in tissue-engineered bone constructs.