Method: 0.1 mM Si4+ treatments were prepared by dissolving Na2SiO3 in basal medium (α-MEM, 10% fetal bovine serum, 1% penicillin–streptomycin, 50 mg L-1 ascorbic acid (control medium)). Osteoblasts (MC3T3-E1 subclone 4) were treated with (1) control medium, (2) control medium after OSX siRNA knockdown, (3) Si4+ treated control medium, and (4) Si4+ treated control medium after OSX siRNA knockdown. Cells were cultured for 3 days, lysed for mRNA, converted to cDNA, and amplified for OSX and Col(V)α3 relative expression using qPCR. Cells on cover slips were cultured for 6 days under treatments (1) and (3), fixed, stained (Picrosirius Red) and imaged for collagen fiber bundle formation using polarized light microscopy.
Result: Si4+ treatments induced a two-fold increase in OSX and Col(V)α3 expression after 3 days in culture relative to control treated cells. When OSX siRNA knockdown was applied to osteoblasts, Si4+ treatments did not enhance the expression of OSX or Col(V)α3. Imaging results revealed increased density of collagen fiber bundle formation in Si4+ treatments after 6 days as compared to control treatments.
Conclusion: Si4+ treatments enhanced collagen ECM formation through the enhanced expression of OSX transcription and Col(V)α3 gene expression.
Keywords: Biomaterials, Collagen, Gene expression and Osteoblasts/osteoclasts