Long wave ultrasound may enhance bone regeneration by altering OPG/RANKL ratio in human osteoblast-like cells.
Human osteoblast cell line (MG63) cells were treated with long wave (45 kHz, intensity 30 mW/cm(2)) continuous ultrasound (US) for 5 min and incubated for various time periods following the treatment. The reverse transcriptase polymerase chain reaction (RT-PCR) technique was used for observing the genetic expression and real-time PCR for quantitative analysis of receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) along with alkaline phosphatase (ALP), an early bone marker, and osteocalcin (OCN) a late marker. ELISA was performed to estimate the amount of the cytokine released into the culture media. The osteoblasts responded to US by significantly upregulating both the OPG mRNA and protein levels. There was no RANKL mRNA expression observed in both the US and control groups and the protein levels were also very low in both groups. There was also no TNF-alpha expression and the TNF-alpha protein levels were insignificant. ALP and OCN mRNA were significantly upregulated in the US group. To our knowledge, this is the first study that shows the effect of US on OPG, RANKL and TNF-alpha expression. US appears to upregulate OPG and may downregulate RANKL production. From these findings, we conclude that therapeutic ultrasound may increase bone regeneration by altering the OPG/RANKL ratio in the bone microenvironment.
Eastman Dental Institute, UCL, 256 Grays Inn Road, London WC1X 8LD, England, UK.
Abhiram
A
Maddi
Hokee
H
Hai
Siew-Tin
ST
Ong
Lindsay
L
Sharp
Malcolm
M
Harris
Sajeda
S
Meghji
D000469:Alkaline Phosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001861:Bone Regeneration / Q000528:radiation effects*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D003470:Culture Media / Q000032:analysis / Q000737:chemistry; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism*; D010006:Osteoblasts / Q000528:radiation effects*; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger / Q000378:metabolism; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D013997:Time Factors; D014465:Ultrasonics
D015415:Biomarkers; D002352:Carrier Proteins; D003470:Culture Media; D006023:Glycoproteins; D008024:Ligands; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D000469:Alkaline Phosphatase