Effect of mechanical fluid flow on calcium deposition of dental pulp stem cells

Abstract

Cleft lip and/or palate is a congenital disorder with a high incidence in Thailand (0.11-0.24%). To fill the defect with autologous bone graft is the gold standard of treatment, however resulting in donor site morbidity, more operation time and time to stay at hospital. Bone tissue engineering may be used to restore such problems with mechanosensitive cells which enhance a bone production. Dental pulp cells (DPCs) are one of the promising cell sources which are collected from human dental pulp tissues. Oscillatory fluid flow (OFF) has been shown to enhance bone production in osteoprogenitor cells. However, the frequency of OFF for increasing bone production is still unclear. This study aimed to determine whether the frequencies of OFF enhance the DPCs’ osteogenesis. DPCs from 3 donors were cultured in an osteogenic medium and rocked under an incubated rocking shaker at frequencies of 10, 20, 30, 40, and 50 rounds per minute (RPM) for 1 hour/day, 5 days/week compared to a static group (0 RPM) from day 4 of culture. Cell proliferation was measured by measuring the total protein and osteogenic activity was measured by alkaline phosphatase (ALP) activity and calcium deposition on days 7, 14, and 21 of culture. DPCs’ in the 30 rpm group produced more calcium deposition, suggesting the best frequency in enhancing osteogenesis in the human DPCs. High frequency (50 RPM) showed negative effect on cell proliferation. The results were consistent with the previous study that a low shear stress (less than 1 Pa) could promote cell differentiation. The method using the incubated rocking shaker may be a simple treatment and cost effective method for producing cells in bone tissue engineering to restore cleft defects. More donors of DPCs will be used for reducing cell variation and extended days of culture for receiving more results in future work.

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