Author: Hu B1, Zhang Y2, Zhou J1, Li J1, Deng F1, Wang Z3, Song J1.
Affiliation: 1Chongqing key Laboratory for Oral Diseases and Biomedical Sciences, Chongqing, China; College of Stomatology, Chongqing Medical University, Chongqing, China. 2Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America. 3College of Biomedical Engineering, Chongqing Medical University, Chongqing, China.
Conference/Journal: PLoS One.
Date published: 2014 Apr 17
Other:
Volume ID: 9 , Issue ID: 4 , Pages: e95168 , Special Notes: doi: 10.1371/journal.pone.0095168. , Word Count: 287
Human periodontal ligament cells (hPDLCs) possess stem cell properties, which play a key role in periodontal regeneration. Physical stimulation at appropriate intensities such as low-intensity pulsed ultrasound (LIPUS) enhances cell proliferation and osteogenic differentiation of mesechymal stem cells. However, the impacts of LIPUS on osteogenic differentiation of hPDLCs in vitro and its molecular mechanism are unknown. This study was undertaken to investigate the effects of LIPUS on osteogenic differentiation of hPDLCs. HPDLCs were isolated from premolars of adolescents for orthodontic reasons, and exposed to LIPUS at different intensities to determine an optimal LIPUS treatment dosage. Dynamic changes of alkaline phosphatase (ALP) activities in the cultured cells and supernatants, and osteocalcin production in the supernatants after treatment were analyzed. Runx2 and integrin β1 mRNA levels were assessed by reverse transcription polymerase chain reaction analysis after LIPUS stimulation. Blocking antibody against integrinβ1 was used to assess the effects of integrinβ1 inhibitor on LIPUS-induced ALP activity, osteocalcin production as well as calcium deposition. Our data showed that LIPUS at the intensity of 90 mW/cm2 with 20 min/day was more effective. The ALP activities in lysates and supernatants of LIPUS-treated cells started to increase at days 3 and 7, respectively, and peaked at day 11. LIPUS treatment significantly augmented the production of osteocalcin after day 5. LIPUS caused a significant increase in the mRNA expression of Runx2 and integrin β1, while a significant decline when the integrinβ1 inhibitor was used. Moreover, ALP activity, osteocalcin production as well as calcium nodules of cells treated with both daily LIPUS stimulation and integrinβ1 antibody were less than those in the LIPUS-treated group. In conclusion, LIPUS promotes osteogenic differentiation of hPDLCs, which is associated with upregulation of Runx2 and integrin β1, which may thus provide therapeutic benefits in periodontal tissue regeneration.
PMID: 24743551